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Journal of Animal Science and Biotechnology 2024年第1期15卷 396-411页

作者： Shengyang xu Chong Jiao qiyu Diao Yan Tu Beijing Key Laboratory for Dairy Cow nutrition Institute of Feed ResearchChinese Academy of Agricultural SciencesBeijing 100081People’s Republic of China

Background Rumen bacterial groups can affect growth performance,such as average daily gain(ADG),feed intake,and *** study aimed to investigate the inter-relationship of rumen bacterial composition,rumen fermentation indicators,serum indicators,and growth performance of Holstein heifer calves with different *** calves were chosen from a trail with 60 calves and divided into higher ADG(HADG,high pre-and post-weaning ADG,n=6)and lower ADG(LADG,low pre-and post-weaning ADG,n=6)groups to investigate differences in bacterial composition and functions and host *** During the preweaning period,the relative abundances of propionate producers,including g_norank_f_Butyricicoccaceae,g_Pyramidobacter,and g_norank_f_norank_o_Clostridia_vadin BB60_group,were higher in HADG calves(LDA>2,Pnrichment of these bacteria resulted in increased levels of propionate,a gluconeogenic precursor,in preweaning HADG calves(adjusted Pnsequently raised serum glucose concentrations(adjusted Pn contrast,the relative abundances of rumen bacteria in post-weaning HADG calves did not exert this ***,no significant differences were observed in rumen fermentation parameters and serum indices between the two *** The findings of this study revealed that the preweaning period is the window of opportunity for rumen bacteria to regulate the ADG of calves.

关键词： Average daily gain Calves Preweaning period Rumen microbiota

A new monitoring index for ecological vulnerability and its application in the Yellow River Basin,China from 2000 to 2022

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Journal of Arid Land 2024年第9期16卷 1163-1182页

作者： GUO Bing xu Mei ZHAnG Rui LUO Wei School of Civil Engineering and Geomatics Shandong University of TechnologyZibo 255000China Key Laboratory of Remote Sensing of Gansu Province Heihe Remote Sensing Experimental Research StationNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China north China Institute of Aerospace Engineering Langfang 065000China

The ecological environment of the Yellow River Basin has become more fragile under the combined action of natural and manmade ***,the change mechanisms of ecological vulnerability in different sub-regions and periods vary,and the reasons for this variability are yet to be ***,in this study,we proposed a new remote sensing ecological vulnerability index by considering moisture,heat,greenness,dryness,land degradation,and social economy indicators and then analyzed and disclosed the spatial and temporal change patterns of ecological vulnerability of the Yellow River Basin,China from 2000 to 2022 and its driving *** results showed that the newly proposed remote sensing ecological vulnerability index had a high accuracy,at 86.36%,which indicated a higher applicability in the Yellow River *** 2000 to 2022,the average remote sensing ecological vulnerability index of the Yellow River Basin was 1.03,denoting moderate vulnerability *** intensive vulnerability area was the most widely distributed,which was mostly located in the northern part of Shaanxi Province and the eastern part of Shanxi *** 2000 to 2022,the ecological vulnerability in the Yellow showed an overall stable trend,while that of the central and eastern regions showed an obvious trend of *** gravity center of ecological vulnerability migrated southwest,indicating that the aggravation of ecological vulnerability in the southwestern regions was more severe than in the northeastern regions of the *** dominant single factor of changes in ecological vulnerability shifted from normalized difference vegetation index(nDVI)to temperature from 2000 to 2022,and the interaction factors shifted from temperature∩nDVI to temperature∩precipitation,which indicated that the global climate change exerted a more significant impact on regional *** above results could provide decision support for the ecological protection and restoration of the Y

关键词： ecological vulnerability spatio-temporal pattern gravity center migration trajectory interaction factors geodetector green index q-value

Molecular dynamics simulation study of nitrogen vacancy color centers prepared by carbon ion implantation into diamond

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nanotechnology and Precision Engineering 2024年第3期7卷 71-78页

作者： Wei Zhao Zongwei xu Pengfei Wang Hanyi Chen State Key Laboratory of Precision Measuring Technology and Instruments Tianjin UniversityTianjin 300072China Department of Modern Physics University of Science and Technology of ChinaHefei 230026China

nitrogen vacancy(nV)color centers in diamond have useful applications in quantum sensing andﬂuorescent *** can be gen-erated experimentally by ion implantation,femtosecond lasers,and chemical vapor ***,there is a lack of studies of the yield of nV color centers at the atomic *** the molecular dynamics simulations described in this paper,nV color centers are pre-pared by ion implantation in diamond with pre-doped nitrogen and subsequent *** differences between the yields of nV color centers produced by implantation of carbon(C)and nitrogen(n)ions,respectively,are *** is found that C-ion implantation gives a greater yield of nV color centers and superior location *** effects of different pre-doping concentrations(400–1500 ppm)and implantation energies(1.0–3.0 keV)on the nV color center yield are analyzed,and it is shown that a pre-doping concentra-tion of 1000 ppm with 2 keV C-ion implantation can produce a 13%yield of nV color centers after 1600 K annealing for 7.4 ***,a brief comparison of the nV color center identiﬁcation methods is presented,and it is found that the error rate of an analysis utiliz-ing the identify diamond structure coordination analysis method is reduced by about 7%compared with conventional identiﬁcation+methods.

关键词： nV color center Ion implantation Molecular dynamics(MD)simulation Yield enhancement

Spatiotemporal variation and freeze-thaw asymmetry of Arctic sea ice in multiple dimensions during 1979 to 2020

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Acta Oceanologica Sinica 2024年第3期43卷 102-114页

作者： Yu Guo Xiaoli Wang He xu Xiyong Hou CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation Yantai Institute of Coastal Zone ResearchChinese Academy of SciencesYantai 264003China Shandong Key Laboratory of Coastal Environmental Processes Yantai 264003China University of Chinese Academy of Sciences Beijing 100049China

Arctic sea ice is broadly regarded as an indicator and amplifier of global climate *** rapid changes in Arctic sea ice have been widely ***,the spatiotemporal changes in the horizontal and vertical dimensions of Arctic sea ice and its asymmetry during the melt and freeze seasons are rarely quantified simultaneously based on multiple sources of the same long time *** this study,the spatiotemporal variation and freeze-thaw asymmetry of Arctic sea ice were investigated from both the horizontal and vertical dimensions during 1979–2020 based on remote sensing and assimilation *** results indicated that Arctic sea ice was declining at a remarkably high rate of–5.4×10^(4) km^(2)/a in sea ice area(SIA)and–2.2 cm/a in sea ice thickness(SIT)during 1979 to 2020,and the reduction of SIA and SIT was the largest in summer and the smallest in ***,compared with other sub-regions,SIA showed a sharper declining trend in the Barents Sea,Kara Sea,and East Siberian Sea,while SIT presented a larger downward trend in the northern Canadian Archipelago,northern Greenland,and the East Siberian *** to the seasonal trend of sea ice on sub-region scale,the reduction rate of SIA exhibited an apparent spatial heterogeneity among seasons,especially in summer and winter,i.e.,the sub-regions linked to the open ocean exhibited a higher decline rate in winter;however,the other sub-regions blocked by the coastlines presented a greater decline rate in *** SIT,the sub-regions such as the Beaufort Sea,East Siberian Sea,Chukchi Sea,Central Arctic,and Canadian Archipelago always showed a higher downward rate in all ***,a striking freeze-thaw asymmetry of Arctic sea ice was also *** sea ice changes in different dimensions,sea ice over most regions in the Arctic showed an early retreat and rapid advance in the horizontal dimension but late melting and gradual freezing in the vertical *** amount of sea ice me

关键词： Arctic sea ice sea ice area sea ice thickness spatiotemporal variation freeze-thaw asymmetry

Relationship between structure and microwave dielectric properties of Li_(3)Mg_(4)nb_(1-x)Ta_(x)O_(8)ceramics

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Journal of Materiomics 2024年第1期10卷 245-252页

作者： Chongsheng Wu Kui Liu Honglan Lai Fang xu School of Mechanical and Electrical Engineering Chengdu University of TechnologyChengduSichuan610059China School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu610054China State Key Laboratory of Environment-friendly Energy Materials Southwest University of Science and TechnologyMianyang621010China

Herein,the sintering behavior and dielectric properties of Ta5+-doped Li3Mg4nbO8 ceramics were investigated by solid-phase reactions in combination with first-principles *** particular,Li_(3)Mg_(4)nb_(0.96)Ta_(0.04)O_(8)illustrates the best dielectric properties after sintering at 1,175℃withεr=13.71±0.20,q×f=(132,112±2,391)GHz(increased by 25%)andτf=(25.07±1.36)×10^(−6)℃^(−1).The non-intrinsic factors reflect that a small amount of Ta^(5+)doping produces a secondary phase,increased densification,and grain size,all of which optimize the dielectric *** dominant intrinsic factors indicate that the increase in bond ionicity,the greater polarization of Ta^(5+),and the blueshift of the Raman characteristic peak all lead to an increase inε*** increase in lattice energy and the decrease in the damping behavior of the nb/Ta-O bond vibrations lead to an increase in q×*** weakening of the nb/TaO_(6) octahedral distortion leads to an optimization ofτ*** modified Li_(3)Mg_(4)nb_(0.96)Ta_(0.04)O_(8) ceramics have promising applications in microwave communications.

关键词： First-principles Li_(3)Mg_(4)nbO_(8),dielectric properties Lattice vibration

Tailoring sulfur-doped and nitrogen-defective carbon nitride nanosheets for efficient photo-controlled radical polymerizations

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Science China Chemistry 2024年第7期67卷 2325-2334页

作者： xue Li Meng Kai xu Yuan Huang Tao Cai Key Laboratory of Biomedical Polymers of Ministry of Education College of Chemistry and Molecular SciencesWuhan UniversityWuhan 430072China Wuhan University Shenzhen Research Institute Shenzhen 518057China

Despite the challenges that remain,the synergistic adjustment of various microstructures and photochemical parameters of graphitic carbon nitride(g-C_(3)n_(4))in photocatalytic reactions holds promises for improving catalytic efficiency and reducing energy ***,sulfur-doped and nitrogen-defective g-C_(3)n_(4)(n-SC_(3)n_(x))nanosheets were designed and elaborately *** resultant n-SC_(3)n_(x)possessed a precisely defined 2D layer structure with extensive porosity and incremental specific surface *** photoinduced electron transfer-reversible addition-fragmentation chain transfer(PET-RAFT)polymerization of vinyl monomers with low dispersity,excellent temporal control and high chain-end fidelity was achieved under mild blue light irradiation in a nondegassed *** to their ultrathin nanostructures with nitrogen defects and sulfur dopants,n-SC_(3)n_(x)was capable of catalyzing RAFT polymerization in aqueous solutions at significantly accelerated rates,which were nearly 8 times faster compared to bulk g-C_(3)n_(4).The ease of separation and efficient reusability in subsequent polymerizations was enabled by the heterogeneous nature of n-SC_(3)n_(x).The appeal of this approach was illustrated by the fact that utilizing a reusable and metal-free photocatalyst in aqueous environments allowed for the synthesis of polymers with molecular weight up to 300 kg mol^(-1) and a dispersity of 1.32.

关键词： graphitic carbon nitride nitrogen defects sulfur dopants PET-RAFT polymerization recyclability

Self-powered stimuli responsive material for dual stimulation of heat and guest molecules

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Chinese Chemical Letters 2024年第2期35卷 590-593页

作者： Jintao Men Ke xu Taiting Sha Lei He Yan xu Jie Mu Tijian Yin qiong Ye Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics and School of Chemistry and Chemical Engineering Southeast UniversityNanjing 211189China

Stimuli-responsive smart materials exhibit reverse chemical/physical changes in response to external stimuli and research on stimuli-responsive smart materials with self-powered properties is still uncultivated ***,we report perovskite crystalline self-powered multiple stimuli-responsive materials triggered by chemical and thermal stimuli.[HMEP]PbI_(3)·(H_(2)O)(1;HMEP is a hydroxytris(1-methylethyl)phosphorus cation)crystallizes in a chiral space group P 21 at 293 K and has the piezoelectric reaction(d_(33)=10 pC/n and output voltage=1 V)of self-powered modes,this value is larger than the value of 3 pC/n for the classical piezoelectric material *** materials can generate energy due to mechanical deformation,and using thermal heating to lose water,[HMEP]PbI_(3)(2)can be obtained.2 crystallizes in the non-centrosymmetric space group,undergoes two reversible phase transitions at 243/255 K and 315/348 K,and shows second harmonic generation ***,2 can return to the hydrated form 1 after absorbing *** work will lay the foundation for self-powered stimuli-responsive compounds and contribute to the construction of novel organic-inorganic hybrid materials with second harmonic generation switching.

关键词： Self-powered Dual stimulation reactive Phase transition SHG switch Organic-inorganic hybrid perovskite

Atomistic Investigation of Shock-Induced Amorphization within Micro-shear Bands in Hexagonal Close-Packed Titanium

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Acta Metallurgica Sinica(English Letters) 2024年第9期37卷 1590-1600页

作者： Z.C.Meng K.G.Wang T.Ali D.Li C.G.Bai D.S.xu S.J.Li A.H.Feng G.J.Cao J.H.Yao q.B.Fan H.Wang R.Yang Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Interdisciplinary Centre for Additive Manufacturing(ICAM) School of Materials and ChemistryUniversity of Shanghai for Science and TechnologyShanghai 200093China School of Materials Science and Engineering Tongji UniversityShanghai 201804China Key Laboratory for Light-Weight Materials Nanjing Tech UniversityNanjing 210009China national Key Laboratory of Science and Technology on Materials Under Shock and Impact School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401135China

The mechanical response of a single crystal titanium sample against(0001)α surface impact was investigated using molecular dynamics ***,non-uniform plastic deformation was observed in the *** high strain rates,amorphization occurred near the edge of the contact region where severe shear strain induced a large number of stacking faults(SFs)and *** contrast,the central part of the contact region underwent less deformation with significantly fewer ***,instead of amorphization by consuming SFs and dislocations,there was a gradual increase in the density of dislocations and SFs during the process of *** local amorphous regions eventually grew into shear bands.

关键词： Shock compression Amorphization Shear band Titanium Molecular dynamics

A Task Scheduling Algorithm Based on Clustering Pre-processing in Space-Based Information network

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Chinese Journal of Electronics 2024年第1期33卷 217-230页

作者： Yufei WAnG Jun LIU Shengnan ZHAnG Sai xu Jingyi WAnG School of Computer Science and Engineering Northeastern University

With the diversification of space-based information network task requirements and the dramatic increase in demand, the efficient scheduling of various tasks in space-based information network becomes a new challenge. To address the problems of a limited number of resources and resource heterogeneity in the space-based information network, we propose a bilateral pre-processing model for tasks and resources in the scheduling pre-processing stage. We use an improved fuzzy clustering method to cluster tasks and resources and design coding rules and matching methods to match similar categories to improve the clustering effect. We propose a space-based information network task scheduling strategy based on an ant colony simulated annealing algorithm for the problems of high latency of space-based information network communication and high resource dynamics. The strategy can efficiently complete the task and resource matching and improve the task scheduling performance. The experimental results show that our proposed task scheduling strategy has less task execution time and higher resource utilization than other algorithms under the same experimental conditions. It has significantly improved scheduling performance.

关键词： Scheduling algorithms Heuristic algorithms Clustering methods Clustering algorithms Simulated annealing Dynamic scheduling Search problems

Polyethylenimine-modified graphene quantum dots promote endothelial cell proliferation

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Regenerative Biomaterials 2024年第2期3卷 137-146页

作者： qirong xu Chen Li Xiangyan Meng Xinghong Duo Yakai Feng School of Chemistry and Chemical Engineering Qinghai University for NationalitiesXining 810007PR China Key Laboratory of national Ethnic Affairs Commission of Resource Chemistry and Ecological Environment Protection on qinghai-Tibet Plateau Xining 810007PR China institute of Disaster and Emergency Medicine Tianjin UniversityTianjin 300072PR China School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350PR China Key Laboratory of Systems Bioengineering(Ministry of Education) Tianjin UniversityTianjin 300072PR China

Endothelial cell proliferation plays an important role in angiogenesis and treatment of related *** aim of this study was to evaluate the effect of polyethylenimine(PEI)-modified graphene quantum dots(GqDs)gene vectors on endothelial cell *** GqDs-cationic polymer gene vectors were synthesized by amidation reaction,and used to deliver pznF580 gene to Human umbilical vein endothelial cells(HUVECs)for promoting their *** chemical modification of GqDs can ad-just gene vectors'surface properties and charge distribution,thereby enhancing their interaction with gene molecules,which could effectively compress the pZnF580 *** CCK-8 assay showed that the cell viability was higher than 80%at higher vector concentration(40μg/mL),demonstrating that the GqDs-cationic polymer gene vectors and their gene complex nanoparticles(nPs)having low *** results of the live/dead cell double staining assay were consistent with those of the CCK-8 assay,in which the cell viability of the A-GqDs/pZnF580(94.38±6.39%),C-GqDs-PEI-polylactic acid-co-polyacetic acid(PLGA)/pZnF580(98.65±6.60%)and n-GqDs-PEI-PLGA/pZnF580(90.08±1.60%)groups was significantly higher than that of the Lipofectamine 2000/pznF580(71.98±3.53%)positive treatment *** results of transfection and western blot experiments showed that the vector significantly enhanced the delivery of plasmid to HUVECs and increased the expression of pZnF580 in *** addition,the gene nPs better promote endothelial cell migration and *** cell migration rate and proliferation ability of C-GqDs-PEI-PLGA/pZnF580 and n-GqDs-PEI-PLGA/pZnF580 treatment groupS were higher than those of Lipofectamine 2000/pDnA treatment *** GqDs possess the potential to serve as efficient gene *** tightly bind gene molecules through charge and other non-covalent interactions,significantly improving the effciency of gene delivery and ensuring the smooth release of genes with

关键词： graphene quantum dots polyethylenimine ZnF580 gene endothelial cell proliferation