检索结果-南通市图书馆

Prediction of the ^(13)C NMR Chemical Shifts of Stilbene Analogues by GIAO Method

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2010年第6期26卷 1016-1019页

作者： XIE Hui-ding LI Yu-peng QIU kai-xiong LIU bo chen Ya-ping Department of Chemistry School of Pharmaceutical Sciences Kunming Medical College Kunming 650500 P. R. China

After the geometry optimization at B3LYP/6-31＋G（d,p） level,the calculations of the NMR chemical shifts of a series of stilbene analogues were carried out by means of Gauge Including Atomic Orbitals（GIAO） method at HF/6-31＋G（d） level and B3LYP/6-311G＋（2d,p） level,*** 13C NMR chemical shifts calculated at both HF/6-31＋G（d） and B3LYP/6-31＋G（d,p） levels are in agreement with the observed *** virtue of a series of linear correction equations（δpred.=a＋bδcalcd.） of the 13C chemical shifts,accurate prediction of 13C chemical shifts was achieved for the new stilbene *** the 13C NMR chemical shifts calculated at HF/6-31＋G（d） level,the linear correlation of δ*** δ*** excellent,and the square of correlation coefficient,r2,is *** maximum absolute difference between δ*** δexptl.,Δδ,is 2.3,and the root-mean-square error between δ*** δ*** *** the meantime,for those obtained at B3LYP/6-31＋G（d,p） level,the linear correlation of δ*** δ*** also excellent,and the square of correlation coefficient,r2,is up to *** maximum absolute difference between δ*** δexptl.,Δδ,is 2.2,and the root-mean-square error between δ*** δ*** only 0.88.

关键词： Stilbene analogue ^13C NMR chemical shift Prediction

One-pot synthesis of network supported catalyst using supramolecular gel as template

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2010年第8期21卷 991-994页

作者： Yong Liang Li Ming Tang Yu Xia kai chen bo Tian Li Xin Jin Laboratory of Advanced Materials Department of Chemical EngineeringTsinghua UniversityBeijing 100084China

A simple and general strategy is described for preparing network supported catalyst through a one-pot synthetic procedure using supramolecular gel as *** procedure directly attaches ligand to support during fabricating the *** this strategy,supported CuBr/di-（2-picolyl） amine catalyst with U-shaped fibrillar network was prepared and used in atom transfer radical polymerization of methyl *** and SEM characterization of the catalyst revealed homogeneous distribution of ligand,sufficient reactive sites,adequate mechanical strength and *** polymerization results demonstrated high activity and reusability of such *** strategy might be extended to other supported catalysts used in column reactors.

关键词： One-pot synthesis Network supported catalyst Supramolecular gel Atom transfer radical polymerization

Enhancement of low-temperature toughness of Fe-Mn-C-Al alloy by rare earth Ce-modified inclusions

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第1期31卷 157-173页

作者： Guang-kai Yang Chang-ling Zhuang Yi-zhuang Li chen Hu Shao-bo Li College of Materials and Metallurgy Guizhou UniversityGuiyang550025GuizhouChina Department of Mechanical Engineering University of Hong KongHong Kong999077China The State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819LiaoningChina State Key Laboratory of Public Big Data Guizhou UniversityGuiyang550025GuizhouChina

Fe-Mn-C-Al alloys have been recognized as promising materials for certain low-temperature applications due to their exceptional mechanical properties and ***,their limited low-temperature toughness restricts their large-scale applications in specific *** influence of trace amounts of rare earth cerium(Ce)on the low-temperature toughness of Fe-18Mn-0.6C-1.8Al alloys was *** addition of Ce effectively alters the inclu-sions in the alloy,transforming large-sized irregular inclusions into fine ellipsoidal rare earth *** leads to a significant reduction in both the proportion and average size of the inclusions,resulting in their effective dispersion throughout the matrix and improved cryogenic *** presence of Ce-containing inclusions within the matrix reduces stress concentration,thereby inhibiting microcrack formation and improving impact absorption ***-cally,the addition of rare earth Ce alters the fracture behavior of the material at room temperature and low temperature,changing from brittle cleavage fracture to a more ductile failure *** impact toughness of the Fe-Mn-C-Al alloy is significantly improved by the addition of 0.0048 wt.%Ce,particularly at-196℃where the impact toughness reaches 103.6 J/cm^(2),representing an impressive improvement of 87.3%.

关键词： Fe-Mn-C-Al alloy Rare earth Low-temperature toughness Inclusion Fracture

A novel method for calculating broadband electrical performance of high-speed aircraft radome under thermo-mechanical-electrical coupling

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

Chinese Journal of Aeronautics 2024年第9期37卷 463-474页

作者： Jianmin JI Jianhua REN Xunya JIANG Wei WANG Huilong YU kai YIN bo chen Beijing Institute of Remote Sensing Equipment Beijing 100854China Shanghai Dong Jun Information and Technology Co.Ltd Shanghai 200050China

The electrical performance of radomes on high-speed aircraft can be influenced by the thermal and mechanical loads produced during high-speed flight,which can affect the detection dis-tance and accuracy of the guidance *** paper presents a new method that uses the Finite Difference Time Domain(FDTD)method to calculate the electrical performance of radomes under Thermo-Mechanical-Electrical(TME)*** method can accurately characterize the effects of material dielectric temperature drift and structural deformation on the electrical performance of the radome under flight conditions,enabling high-precision full-wave calculations of the broadband electrical performance of the *** method initiates by utilizing a Finite Element Grid Model(FE-GM)of the radome to sequentially acquire the radome's response temperature field and structural deformation field through thermal and mechanical ***,spatial mapping techniques are developed to accurately incorporate the dielectric temperature drift and structural deformation of the radome into its Yee grid Electromagnetic(EM)simulation model.A verification case was designed to test the proposed method,and the results confirmed its high computational ***,the effectiveness and necessity of the method were further demonstrated by analyzing the electrical performance of a fused silica ceramic radome used on a high-speed aircraft.

关键词： High-speed aircraft Radomes Thermo-Mechanical-Electrical(TME)coupling Finite Difference Time Domain(FDTD)method Spatial mapping

Single-cell transcriptomes provide insights into expansion of glial cells in bombyx mori

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

Insect Science 2024年第4期31卷 1041-1054页

作者： Xiaojing Liu Zhongjie Zhang bo Hu kai chen Ye Yu Hui Xiang Anjiang Tan Jiangsu Key Laboratory of Sericultural Biology and Biotechnology School of BiotechnologyJiangsu University of Science and TechnologyZhenjiangJiangsu ProvinceChina Key Laboratory of Silkworm and Mulberry Genetic Improvement Ministry of Agriculture and Rural AffairsThe Sericultural Research InstituteChinese Academy of Agricultural SciencesZhenjiangJiangsu ProvinceChina Guangzhou Key Laboratory of Insect Development Regulation and Application Research Institute of Insect Science and Technology and School of Life SciencesSouth China Normal UniversityGuangzhouChina

The diversity of cell types in the brain and how these change during different developmental stages,remains largely *** life cycle of insects is short and goes through 4 distinct stages including embryonic,larval,pupal,and adult *** postembryonic life,the larval brain transforms into a mature adult version after *** silkworm,bombyx mori,is a lepidopteran model ***,we characterized the brain cell repertoire of larval and adult *** by obtaining 50708 single-cell *** and 12 cell clusters from larval and adult brains were assigned based on marker genes,*** cell types include Kenyon cells,optic lobe cells,monoaminergic neurons,surface glia,and astrocyte *** further assessed the cell type compositions of larval and adult *** found that the transition from larva to adult resulted in great expansion of glial *** glial cell accounted for 49.8%of adult midbrain *** to flies and ants,the mushroom body kenyon cell is insufficient in ***,which accounts for 5.4%and 3.6%in larval and adult brains,*** of neuropeptide expression showed that the abundance and specificity of expression varied among individual ***,we found that ion transport peptide was specifically expressed in glial cells of larval and adult *** cell atlas dataset provides an important resource to explore cell diversity,neural circuits and genetic profiles.

关键词： brain neuropeptide silkworm single-cell transcriptome

p38 Signaling Mediates Naringin-Induced Osteogenic Differentiation of Porcine Metanephric Mesenchymal Cells

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

Chinese Journal of Integrative Medicine 2024年第9期30卷 818-825页

作者： JI Peng-cheng XIE Yuan-sheng GUO Wen-kai FU bo chen Xiang-mei Chinese PLA Medical School Beijing100853China Department of Nephrology First Medical Center of Chinese PLA General HospitalChinese PLA Institute of NephrologyState Key Laboratory of Kidney DiseasesNational Clinical Research Center for Kidney DiseasesBeijing Key Laboratory of Kidney DiseasesBeijing100853China School of Medicine Nankai UniversityTianjin300071China

Objective:To explore the potential of metanephric mesenchymal cells(MMCs)for osteogenesis and naringin’s ability to enhance this process and its molecular ***:Porcine MMCs at 70 days of gestation were used as tool cells,cultured in osteogenic induction medium,identified by immunocytochemistry *** potential of porcine MMCs and naringin’s ability to enhance this process was tested by detecting changes in cell viability,alkaline phosphatase(ALP)activity,the expression of runt-related transcription factor 2(Runx2),osteopontin(OPN)and osteocalcin(OCN),and the formation of mineralized nodules,and the application of the p38 signaling pathway inhibitor SB203580 vitiated the osteogenesis-promoting effect of ***:Immunocytochemical staining showed that the cells were Vimentin and Six2(+),E-cadherin and CK-18(−).Naringin can activate the p38 signaling pathway to enhance the osteogenesis of porcine MMCs by increasing cell viability,ALP activity,the expressions of Runx2,OPN and OCN,and the formation of mineralized nodules(Pbone,enhances the osteogenic differentiation of renal MMCs through the p38 signaling pathway.

关键词： metanephric mesenchymal cells naringin osteogenesis differentiation

Adaptive state-constrained/model-free iterative sliding mode control for aerial robot trajectory tracking

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 603-618页

作者： chen AN Jiaxi ZHOU kai WANG College of Mechanical and Vehicle Engineering Hunan UniversityChangsha 410082China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHong KongChina

This paper develops a novel hierarchical control strategy for improving the trajectory tracking capability of aerial robots under parameter *** hierarchical control strategy is composed of an adaptive sliding mode controller and a model-free iterative sliding mode controller(MFISMC).A position controller is designed based on adaptive sliding mode control(SMC)to safely drive the aerial robot and ensure fast state convergence under external ***,the MFISMC acts as an attitude controller to estimate the unmodeled dynamics without detailed knowledge of aerial ***,the adaption laws are derived with the Lyapunov theory to guarantee the asymptotic tracking of the system ***,to demonstrate the performance and robustness of the proposed control strategy,numerical simulations are carried out,which are also compared with other conventional strategies,such as proportional-integralderivative(PID),backstepping(BS),and *** simulation results indicate that the proposed hierarchical control strategy can fulfill zero steady-state error and achieve faster convergence compared with conventional strategies.

关键词： aerial robot hierarchical control strategy model-free iterative sliding mode controller(MFISMC) trajectory tracking reinforcement learning

Reactive transport modeling constraints on the complex genesis of a lacustrine dolomite reservoir: A case from the Eocene Qaidam Basin,China

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第4期21卷 2240-2256页

作者： Ying Xiong bo Liu Xiu-cheng Tan Zheng-Meng Hou Jia-Shun Luo Ya-chen Xie kai-bo Shi Kun-Yu Wu School of Earth and Space Sciences Peking University Institute of Oil and Gas Peking University China National Petroleum Corporation Key Laboratory of Carbonate Reservoirs Southwest Petroleum University Institute of Subsurface Energy Systems Clausthal University of Technology Research Institute of Exploration and Development PetroChina Qinghai Oil Field Company

Reactive transport modeling(RTM) is an emerging method used to address geological issues in diagenesis research. However, the extrapolation of RTM results to practical reservoir prediction is not sufficiently understood. This paper presents a case study of the Eocene Qaidam Basin that combines RTM results with petrological and mineralogical evidence. The results show that the Eocene Xiaganchaigou Formation is characterized by mixed siliciclastic-carbonate-evaporite sedimentation in a semiclosed saline lacustrine environment. Periodic evaporation and salinization processes during the syngeneticpenecontemporaneous stage gave rise to the replacive genesis of dolomites and the cyclic enrichment of dolomite in the middle-upper parts of the meter-scale depositional sequences. The successive change in mineral paragenesis from terrigenous clastics to carbonates to evaporites was reconstructed using RTM simulations. Parametric uncertainty analyses further suggest that the evaporation intensity(brine salinity) and particle size of sediments(reactive surface area) were important rate-determining factors in the dolomitization, as shown by the relatively higher reaction rates under conditions of higher brine salinity and fine-grained sediments. Combining the simulation results with measured mineralogical and reservoir physical property data indicates that the preservation of original intergranular pores and the generation of porosity via replacive dolomitization were the major formation mechanisms of the distinctive lacustrine dolomite reservoirs(widespread submicron intercrystalline micropores) in the Eocene Qaidam Basin. The results confirm that RTM can be effectively used in geological studies, can provide a better general understanding of the dolomitizing fluid-rock interactions, and can shed light on the spatiotemporal evolution of mineralogy and porosity during dolomitization and the formation of lacustrine dolomite reservoirs.

关键词： Reactive transport modeling Lacustrine dolomite Mineralogy and porosity evolution Reservoir genesis

Model-driven full system dynamics estimation of PMSM-driven chain shell magazine

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第9期39卷 147-156页

作者： kai Wei Longmiao chen Quan Zou School of Mechanical Engineering NanJing University of Science and TechnologyNanjing210094China

Based on the system dynamic model, a full system dynamics estimation method is proposed for a chain shell magazine driven by a permanent magnet synchronous motor(PMSM). An adaptive extended state observer(AESO) is proposed to estimate the unmeasured states and disturbance, in which the model parameters are adjusted in real time. Theoretical analysis shows that the estimation errors of the disturbances and unmeasured states converge exponentially to zero, and the parameter estimation error can be obtained from the extended state. Then, based on the extended state of the AESO, a novel parameter estimation law is designed. Due to the convergence of AESO, the novel parameter estimation law is insensitive to controllers and excitation signal. Under persistent excitation(PE) condition, the estimated parameters will converge to a compact set around the actual parameter value. Without PE signal, the estimated parameters will converge to zero for the extended state. Simulation and experimental results show that the proposed method can accurately estimate the unmeasured states and disturbance of the chain shell magazine, and the estimated parameters will converge to the actual value without strictly continuous PE signals.

关键词： Chain shell magazine Full system dynamics estimation Disturbance estimation Parameter estimation Adaptive extended state observer