检索结果-南通市图书馆

Photoredox-catalyzed C-glycosylation of peptides with glycosyl bromides

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第6期35卷 263-267页

作者： chen Li Ziyuan Zhao Shouyun Yu State Key Laboratory of Analytical Chemistry for Life Science Jiangsu Key Laboratory of Advanced Organic MaterialsChemistry and Biomedicine Innovation Center(ChemBIC)School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

Glycosyl radicals,produced under mild photoredox conditions,show unique utility in the preparation of C-linked *** herein report the construction of C-glycosidic bonds on α,β-dehydroalanine(DHA)of peptides with easily available glycosyl bromides as glycosyl radical precursors under highly anomeric control,leading to C-glycosylation modifications of *** method not only has outstanding functional group compatibility,but also is feasible in near-physiological conditions(pH~7 and temperature t≤37℃ in aqueous media).

关键词： Glycosylation C-Glycosides Glycopeptides Dehydroalanine Photoredox catalysis

UAV swarm air combat maneuver decision-making method based on multi-agent reinforcement learning and transferring

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第8期67卷 49-66页

作者： Zhiqiang ZHENG chen WEI Haibin DUAN State Key Laboratory of Virtual Reality technology and Systems School of Automation Science and Electrical Engineering Beihang University

During short-range air combat involving unmanned aircraft vehicle(UAV) swarms, UAVs must make accurate maneuver decisions based on information from both enemy and friendly UAVs. this dual requirement of competition and cooperation presents a significant challenge in the field of unmanned air combat. In this paper, a method based on multi-agent reinforcement learning(MARL) is proposed to address this issue. An actor network containing three subnetworks that can handle different types of situational information is designed. Hence, the results from simpler one-on-one scenarios are leveraged to enhance the complex swarm air combat training process. Separate state spaces for local and global information are designed for the actor and critic networks. A detailed reward function is proposed to encourage *** prevent lazy participants in air combat, a reward assignment operation is applied to distribute these dense rewards. Simulation testing and ablation experiments demonstrate that both the transfer operation and reward assignment operation can effectively deal with the swarm air combat scenario, and reflect the effectiveness of the proposed method.

关键词： UAV swarm short-range air combat multi-agent reinforcement learning reward assignment transfer

Preparation,optical properties and energy transfer of SrLaAlO4:Dy3+,Eu3+

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第11期42卷 2058-2067页

作者： Wei chen Heng Zhang Desheng Zhu School of Physic and Optoelectronic Engineering Yangtze University

A series of Dy3+/Eu3+single doped and co-doped SrLaAlO4phosphors was synthesized by the traditional high-temperature solid-state method,and their structure,morphology and optical properties were *** x-ray diffraction（xRD） shows a small amount of doping with Dy3+and Eu3+does not change the crystal structure of the matrix SrLaAlO4and the best synthesis temperature is 1450℃.the scanning electron microscopy（SEM） indicates the particle size directly ranges from 1 to 5μm roughly and the energy dispersive spectroscopy（EDS） patterns show that SrLaAlO4:Dy3+phosphor and SrLaAlO4:Dy3+,Eu3+phosphor were successfully ***4:Dy3+phosphor can be effectively excited by near-ultraviolet light,producing two strong emission lights at 483 nm（blue light） and 579 nm（yellow light）,presenting a cold white light;SrLaAlO4:Eu3+phosphor can be effectively excited by nearultraviolet light,producing red lights at 622 nm;the characteristic emission peaks of Dy3+and Eu3+can be shown simultaneously under the same excitation wavelength in SrLaAlO4:Dy3+, Eu3+*** changing the relative doping concentration ratio of Dy3+and Eu3+,the modulation of SrLaAlO4:Dy3+,Eu3+phosphor from cold white to warm white light can be *** addition,the study of the luminescent mechanism and lifetime shows that there is energy transfer between Dy3+and Eu3+in SrLaAlO4:Dy3+,Eu3+phosphor.

关键词： Energy transfer High-temperature solid-phase method Luminescence properties Rare earths SrLaAlO4: Dy3+, Eu3+ White phosphor

High association strengths are linked to phenotypic similarity,including plumage color and patterns,of participants in mixed-species bird flocks of southwestern China

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2024年第1期70卷 34-44页

作者： Liping Zhou Christos Mammides Youfang chen Wenyi Zhou Wenzhang Dai Edward L.Braun Rebecca t.Kimball Yang Liu Scott K.Robinson Eben Goodale Guangxi Key Laboratory of Forest Ecology and Conservation College of ForestryGuangxi UniversityNanning 530004China Kunming Natural History Museum of Zoology Kunming Institute of ZoologyChinese Academy of SciencesKunming 650223China Nature Conservation Unit Frederick University7Yianni Frederickou StreetPallouriotissaNicosia 1036Cyprus State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China Florida Museum of Natural History University of FloridaGainesvilleFL 34201USA Department of Biology University of FloridaGainesvilleFL 34201USA School of Life Science and Institute of Wetland Ecology Nanjing UniversityNanjing 210000China State Key Laboratory of Biocontrol School of EcologySun-Yatsen UniversityGuangzhou 510275China Department of Health and Environmental Science Xi'an Jiaotong Liverpool UniversitySuzhou 215123China

Participants in mixed-species bird flocks(MSFs)have been shown to associate with species that are similar in body size,diet,and evolutionary history,suggesting that facilitation structures these *** addition,several studies have suggested that species in MsFs resemble each other in their plumage,but this question has not been systematically investigated for any MsF *** the nonbreeding season of 2020 and 2021,we sampled 585 MSFs on 14 transects in 2 habitats of tongbiguang Nature Reserve in western Yunnan Province,*** performed social network analysis and the Multiple Regression Quadratic Assignment Procedure to evaluate the effect of 4 species traits(body size,overall plumage color,distinctive plumage patterns,and diet)and evolutionary history on species association strength at the whole-MSF and within-MSF *** 41 significant relationships showed that species with stronger associations were more similar in their various *** size had the strongest effect on association strength,followed by phylogeny,plumage patterns,and plumage color;diet had the weakest *** results are consistent with the hypotheses that the benefits of associating with phenotypically similar species outweigh the potential costs of interspecific competition,and that trait matching can occur in plumage characteristics,albeit more weakly than in other *** explanations exist as to why similarities in plumage may occur in MSFs,including that they could reduce predators'ability to target phenotypically"odd"*** trait matching in plumage occurs through assortative processes in ecological time or is influenced by co-evolution requires furtherstudy.

关键词： co-evolution interaction networks mixed-species animal groups phenotypic similarity trait convergence

Simulation design of thin film lithium niobate electro-optic modulator with bimetallic layer electrodes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Optoelectronics Letters 2024年第6期20卷 339-345页

作者： WU Qiulin FENG xinkai chen Jiaying MA Lei chen Huaixi LIANG Wanguo Fujian Institute of Research on the Structure of Matter Chinese Academy of SciencesFuzhou 350108China University of Chinese Academy of Sciences Beijing 100059China Fujian Science&technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108China1

thin-film lithium niobate electro-optical modulator will become the key device in the future optical communication,which has the advantages of high modulation rate,low half-wave voltage,large bandwidth,and easy integration compared with conventional bulk lithium niobate ***,because the electrode gap of the lithium niobate film modulator is very narrow,when the microwave frequency gets higher,it leads to higher microwave loss,and the electro-optical performance of the modulator will be greatly ***,we propose a thin film lithium niobate electro-optic modulator with a bimetallic layer electrode structure to achieve microwave loss less than 8 dB/cm in the range of 200 GHz,exhibiting a voltage-length product of 1.1 V·cm and a 3 dB electro-optic bandwidth greater than 160 ***-speed data transmission test has been performed,showing good performance.

关键词： Simulation design of thin film lithium niobate electro-optic modulator with bimetallic layer electrodes

tailoring the texture and mechanical properties of 3%Y_(2)O_(3)p/ZGK200 composites fabricated by unidirectional and cross rolling followed by annealing

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第4期12卷 1479-1495页

作者： xihai Li Hong Yan Zhiwei Shan Rongshi chen Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering University of Science and Technology of China72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering Shandong University of Science and TechnologyQingdaoShandong 266590China Center for Advancing Materials Performance from the Nanoscale(CAMP-Nano)and Hysitron Applied Research Center in China(HARCC) State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an 710049China

3%Y_(2)O_(3)p/ZGK200 composites were subjected to unidirectional rolling(UR)and cross rolling(CR)at 400℃and 350℃followed by annealing at 300℃for 1 *** microstructure,texture and mechanical properties of rolled and annealed composites were systematically *** rolled composites exhibited a heterogeneous microstructure,consisting of deformed grains elongated along rolling direction(RD)and Y_(2)O_(3)particles bands distributed along *** annealing,static recrystallization(SRx)occurred and most deformed grains transformed into equiaxed grains.A non-basal texture with two strong t-texture components was obtained after UR while a non-basal elliptical/circle texture with circle multi-peaks was obtained after CR,indicating that rolling path had great influences on texture of the *** annealing process,R-texture component disappeared or weakened,as results,a non-basal texture with double peaks tilting from normal direction(ND)to transverse direction(tD)and a more random non-basal texture with circle multi-peaks were obtained for UR and CR composites,*** yield strength of rolled composites after UR showed obvious anisotropy along RD and tD while a low anisotropic yield strength was obtained after *** Y_(2)O_(3)particles broke during *** fracture of the composites was attributed to the existence of Y_(2)O_(3)clusters and interfacial debonding between particles and matrix during tension,as a result,the ductility was not as superior as matrix alloy.

关键词： Magnesium matrix composites Unidirectional rolling Cross rolling texture Mechanical properties

Combined effect of WS_(2) and ti_(3)C_(2)t_(x) Mxene favors oil-based ultra-low friction on rough steel-steel interface at elevated temperatures

在线全文

学校读者我要写书评

暂无评论

Science China(technological Sciences) 2024年第7期67卷 1991-2002页

作者： LIU YangQin chen Lei WANG Yang QIAN LinMao tribology Research Institute State Key Laboratory of Rail Transit Vehicle SystemSchool of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China Key Laboratory of Advanced technologies of Materials(Ministry of Education) Research Institute of Frontier ScienceSouthwest Jiaotong UniversityChengdu 610031China

the lubrication performance of liquids is severely restricted and is degraded in high-temperature environments. Stable and reliable lubrication in high temperature environments has been a long-standing goal in various industrial fields. In this study,WS_(2)and ti_(3)C_(2)t_(x)Mxene nanoflakes were used as oil-based lubricant additives to generate ultra-low friction and even superlubricity(friction coefficient of ~0.007) at elevated temperatures(400℃), which has hitherto not been achieved by both individual pristine materials, WS_(2)and ti_(3)C_(2)t_(x)Mxene. Viscosity and thermogravimetric characterization revealed improvements in the high-temperature rheological properties and thermal stability of the lubricating base oil, indicating improved loadbearing and continuous lubrication capabilities at elevated temperatures. x-ray photoelectron spectroscopy, transmission electron microscopy, and atomic force microscopy demonstrated that the formation of an iron/titanium/tungsten-rich oxide lubricious thin film at the sliding interface reduced the interfacial shear stress, which was responsible for the observed friction and wear reductions at high contact pressures(> 1.1 GPa). Although the titanium/tungsten oxide film was gradually removed after prolonged sliding, a sufficiently thick iron oxide film maintained a low friction coefficient for at least 2 h. the improved surface quality facilitates the achievement of ultra-low friction and reduced wear. the proposed lubrication methodology has a broad utilization potential as a wear-reduction strategy across various industrial fields at elevated temperatures.

关键词： ultra-low friction high-temperature wear reduction lubricating additive tungsten disulfide Mxene

Semiconductor fibers for textile integrated electronic systems

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第6期11卷 100-101页

作者： Yuanyuan Zheng Zhen Wang Peining chen Huisheng Peng State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceInstitute of Fiber Materials and Devices and Laboratory of Advanced Materials Fudan University

Over 5000 years of development, the functions of clothing have been mainly limited in warmth and modesty. With the development of smart fibers, fabrics are anticipated to revolutionize multidisciplinary applications, ... 详细信息

关键词： Fibers

Hypoglycemic mechanism of tegillarca granosa polysaccharides on type 2 diabetic mice by altering gut microbiota and regulating the PI3K-akt signaling pathwaye

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2024年第2期13卷 842-855页

作者： Qihong Jiang Lin chen Rui Wang Yin chen Shanggui Deng Guoxin Shen Shulai Liu xingwei xiang College of Food Science and technology Zhejiang University of TechnologyHangzhou 310014China Key Laboratory of Marine Fishery Resources Exploitment&Utilization of Zhejiang Province Hangzhou 310014China National R&D Branch Center for Pelagic Aquatic Products Processing(Hangzhou) Hangzhou 310014China Institute of Sericultural and tea Zhejiang Academy of Agricultural SciencesHangzhou 310021China College of Food and Pharmacy Zhejiang Ocean UniversityZhoushan 316000China

type 2 diabetes mellitus(t2DM)is a complex metabolic disease threatening human *** investigated the effects of tegillarca granosa polysaccharide(tGP)and determined its potential mechanisms in a mouse model of t2DM established through a high-fat diet and ***(5.1×10^(3) Da)was composed of mannose,glucosamine,rhamnose,glucuronic acid,galactosamine,glucose,galactose,xylose,and *** could significantly alleviate weight loss,reduce fasting blood glucose levels,reverse dyslipidemia,reduce liver damage from oxidative stress,and improve insulin ***-PCR and Western blotting indicated that tGP could activate the phosphatidylinositol-3-kinase/protein kinase B signaling pathway to regulate disorders in glucolipid metabolism and improve insulin *** increased the abundance of Allobaculum,Akkermansia,and Bifidobacterium,restored the microbiota abundance in the intestinal tracts of mice with t2DM,and promoted short-chain fatty acid *** study provides new insights into the antidiabetic effects of tGP and highlights its potential as a natural hypoglycemic nutraceutical.

关键词： tegillarca granosa polysaccharide type 2 diabetes mellitus Glycolipid metabolism PI3K/Akt signaling pathway