检索结果-南通市图书馆

Al-modified yolk-shell silica particle-supported NiMo catalysts for ultradeep hydrodesulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene:Efficient accessibility of active sites and suitable acidity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2024年第1期21卷 654-666页

作者： Ke Yu Wei-Min Kong zhen Zhao ai-Jun Duan Lian Kong Xi-Long Wang State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China Institute of Catalysis for Energy and Environment College of Chemistry and Chemical EngineeringShenyang Normal UniversityShenyang 110034LiaoningChina

Yolk-shell SiO2 particles(YP)with center-radial meso-channels were fabricated through a simple and effective ***-containing YP-supported NiMo catalysts with different Al amounts(NiMo/AYP-x,x=Si/Al molar proportion)were prepared and dibenzothiophene(DBT)and 4,6-dimethyl-dibenzothiophene(4,6-DMDBT)were employed as the probes to evaluate the hydrodesulfurization(HDS)catalytic *** as-prepared AYP-x carriers and corresponding catalysts were characterized by some advanced characterizations to obtain deeper correlations between physicochemical properties and the HDS *** average pore sizes of series AYP-x supports are above 6.0 nm,which favors the mass transfer of organic *** cavity between the yolk and the shell is beneficial for the enrichment of S-containing compounds and the accessibility between reactants and active *** embedded into the silica framework could facilitate the formation of Lewis(L)and Brønsted(B)acid sites and adjust the metal-support interaction(MSI).Among all the as-synthesized catalysts,NiMo/AYP-20 catalyst shows the highest HDS *** improved HDS activity of NiMo/AYP-20 catalyst is attributed to the perfect combination of excellent structural properties of the yolk-shell mesoporous silica,enhanced acidity,moderate MSI,and good accessibility/dispersion of active components.

关键词： Al-containing yolk-shell silica particles Accessibility Acidity Metal-support interaction Hydrodesulfurization

How plant density affects maize spike differentiation, kernel set, and grain yield formation in Northeast China?

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2018年第8期17卷 1745-1757页

作者： ZHANG Ming CHEN Tao Hojatollah Latifmanesh FENG Xiao-min CAO Tie-hua QIAN Chun-rong DENG ai-xing song zhen-wei ZHANG Wei-jian Institute of Crop Sciences Chinese Academy of Agricultural Sciences/Key Laboratory of Crop Physiology and EcologyMinistry of AgricultureBeijing 100081P.R.China Jilin Academy of Agricultural Sciences Changchun 130124P.R.China Heilongjiang Academy of Agricultural Sciences Harbin 150086P.R.China

A two-year field experiment was conducted to evaluate the effects of plant density on tassel and ear differentiation, anthesissilking interval(ASI), and grain yield formation of two types of modern maize hybrids(Zhongdan 909(ZD909) as tolerant hybrid to crowding stress, Jidan 209(JD209) and Neidan 4(ND4) as intolerant hybrids to crowding stress) in Northeast China. Plant densities of 4.50×104(D1), 6.75×104(D2), 9.00×104(D3), 11.25×104(D4), and 13.50×104(D5) plants ha-1had no significant effects on initial time of tassel and ear differentiation of maize. Instead, higher plant density delayed the tassel and ear development during floret differentiation and sexual organ formation stage, subsequently resulting in ASI increments at the rate of 1.2–2.9 days on average for ZD909 in 2013–2014, 0.7–4.2 days for JD209 in 2013, and 0.5–3.7 days for ND4 in 2014, respectively, under the treatments of D2, D3, D4, and D5 compared to that under the D1 treatment. Total florets, silking florets, and silking rates of ear showed slightly decrease trends with the plant density increasing, whereas the normal kernels seriously decreased at the rate of 11.0–44.9% on average for ZD909 in 2013–2014, 2.0–32.6% for JD209 in 2013, and 9.7–28.3% for ND4 in 2014 with the plant density increased compared to that under the D1 treatment due to increased florets abortive rates. It was also observed that 100-kernel weight of ZD909 showed less decrease trend compared that of JD209 and ND4 along with the plant densities increase. As a consequence, ZD909 gained its highest grain yield by 13.7 t ha-1on average at the plant density of 9.00×104 plants ha-1, whereas JD209 and ND4 reached their highest grain yields by 11.7 and 10.2 t ha-1at the plant density of 6.75×104 plants ha-1, respectively. Our experiment demonstrated that hybrids with lower ASI, higher kernel number potential per ear, and relative constant 100-kernel weight(e.g., ZD909) could achieve higher yield under dense planting in high latitude a

关键词： corn dense planting spike differentiation anthesis-silking interval(ASI) kernel set

Investigation of Hole Mobility in GainP/(In) GaAs/GaAs p-Type Modulation Doped Heterostructures

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1999年第1期16卷 50-52页

作者： YANG Quan-kui LI ai-zhen CHEN Jian-xin State Key Laboratory of Functional Materials for Informatics Shanghai Institute of MetallurgyChinese Academy of SciencesShanghai 200050

Ga_(0.51)In_(0.49)P/(In)GaAs/GaAs heterostructure is regarded as an excellent candidate for two dimensional hole gas system as it has a large valence band offset *** this paper,we report the hole mobility in GainP/GaAs and GainP/In_(0.20)G_(0.80)As/GaAs p-type modulation doped heterostructures grown by gas source molecular beam epitaxy with different p-channels and doping *** influences of Be:GaAs cap layer,δ-doping,and strained InGaAs p-channel on hole mobility are discussed,and qualitatively explained by the ionized impurity scattering ***,it was shown that the improvement of hole mobility could be achieved by the δ-doping method combined with strained InGaAs channel.

关键词： GaAs/Ga scattering mobility

Cloning and Expression Pattern of a Gene Encoding a Putative Plastidic ATP/ADP Transporter from Helianthus tuberosus L.

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2005年第9期47卷 1123-1132页

作者： Kun MENG Tuan-Jie CHANG Xiang LIU song-Biao CHEN Yong-Qin WANG ai-Jun SUN Hong-Lin XU Xiao-Li WEI zhen ZHU Institute of Genetics and Developmental Biology the Chinese Academy of Sciences Beijing 100101 China

Herein, we report the cloning and molecular characterization of a full cDNA encoding a putative plastidic ATP/ADP transporter, designated HtAATP, for Helianthus tuberosus L. The ATP/ADP translocator protein was isolated from the tuber-cDNA library of H. tuberosus for the first time. The predicted HtAATP protein was judged as a plastidic ATP/ADP translocator protein from its high homology at the amino acid sequence level to the two Arabidopsis thaliana plastidic ATP/ADP translocator proteins AATP1 and AATP2 （84.8% and 79.9% identity, respectively）. Amino acid sequence analysis of the primary structure of HtAATP revealed that it belonged to the plastidic ATP/ADP transporter family. Hydropathy prediction indicated that HtAATP gene product is a highly hydrophobic membrane protein that contains 10 transmembrane domains to form a spanning topology. Southern blotting analysis showed that the HtAATP gene is a single-copy gene in the H. tuberosus genome. Tissue distribution analysis showed that the HtAATP gene is prominently expressed in sink tissues. A stable expression pattern in tubers at different developmental stages implies an active involvement of HtAATP during carbohydrate formation.

关键词： expression pattern Helianthus tuberosus plastidic ATP/ADP transporter.

Using ^(137)Cs Tracer Technique to Evaluate Erosion and Deposition of Black Soil in Northeast China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pedosphere 2006年第2期16卷 201-209页

作者： FANG Hua-Jun YANG Xue-Ming ZHANG Xiao-Ping LIANG ai-zhen Northeast Institute of Geography and Agricultural Ecology CAS Changchun 130012 （China）. Graduate School of the Chinese Academy of Sciences Beijing 100039 （China） Greenhouse ＆ Processing Crops Research Centre Agriculture ＆ Agri-Food Canada Harrow Ontario NOR 1 GO （Canada）

Soil and water losses through erosion have been serious in the black soil region of Northeast China. Therefore, a sloping cultivated land in songnen Plain was selected as a case study to： 1） determine the ^137Cs reference inventory in the study area; 2） calculate erosion and deposition rates of black soil on different slope locations; 3） conduct a sensitivity analysis of some model parameters; and 4） compare overall outputs using four different models. Three transects were set in the field with five slope locations for each transect, including summit, shoulder-slope, back-slope, foot-slope, and toe-slope. Field measurements and model simulation were used to estimate a bomb-derived ^137Cs reference inventory in the study area. Soil erosion and deposition rates were estimated using four ^137Cs models and percentage of ^137Cs loss/gain. The ^137Cs reference value in the study area was 2 232.8 Bq m^-2 with ^137Cs showing a clear topographic pattern, decreasing from the summit to shoulder-slope, then increasing again at the foot-slope and reaching a maximum at the toe-slope, Predicted soil redistribution rates for different slope locations varied. Among models, the Yang Model （YANG-M） overestimated erosion loss but underestimated deposition. However, the standard mass balance model （MBM1） gave predictions similar to a mass balance model incorporating soil movement by tillage （MBM2）. Sensitivity analysis of the proportion factor and distribution pattern of ^137Cs in the surface layer demonstrated the impact of ^137Cs enrichment on calculation of the soil erosion rate. Factors influencing the redistribution of fallout ^137Cs in landscape should be fully considered as calculating soil redistribution rate using ^137Cs technique.

关键词： black soil cesium-137 (^137Cs) Northeast China quantitative models soil erosion

Bias Free Threshold Estimation for Jump Intensity Function

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2019年第3期34卷 309-325页

作者： LIN Yi-wei LI zhen-wei song Yu-ping School of Mathematics Shandong UniversityJinan 250100China School of Finance and Business Shanghai Normal UniversityShanghai 200234China

In this paper,combining the threshold technique,we reconstruct Nadaraya-Watson estimation using Gamma asymmetric kernels for the unknown jump intensity function of a diffusion process with finite activity *** mild conditions,we obtain the asymptotic normality for the proposed ***,we have verified the better finite-sampling properties such as bias correction and efficiency gains of the underlying estimator compared with other nonparametric estimators through a Monte Carlo experiment.

关键词： Jump-diffusion model Nonparametric estimation Gamma asymmetric kernel

Assessment of the capability of CMIP6 global climate models to simulate Arctic cyclones

在线全文

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2021年第5期12卷 660-676页

作者： song Jia-Ning FU Gang XU Ying HAN zhen-Yu SUN Qi-zhen WANG Hui Ocean University of China Qingdao266100China Laboratory for Climate Studies National Climate CenterChina Meteorological AdministrationBeijing100081China National Marine Environmental Forecasting Center Beijing100081China

Arctic cyclones are one of the important synoptic-scale systems that affect weather variability over the Arctic and can cause intense weather phenomena and ***,research on the assessment of the climate characteristics,activity laws,and variability trends of Arctic cyclones using climate models has practical *** the basis of the fifth-generation European Center for Medium-Range Weather Forecasts reanalysis(ERA5)data,the spatiotemporal variations of Arctic cyclones during 1981–2014 are analyzed by detecting and tracking cyclones using the Lagrangian ***,the simulation results of 14 global climate models from the Coupled Model Intercomparison Project Phase 6(CMIP5)are compared with the results of *** the individual models and their ensemble mean can simulate the spatial distribution of the density of cyclone tracks with reasonable capability,the correlation coefficients of track density are approximately ***,in boreal winter,the Atlantic zonal negative bias of track density is stronger than that in *** contrast,in boreal summer,the negative bias over the Arctic Ocean region is stronger than that in ***,the simulations of density-field-related variables(i.e.,cyclolysis,cyclogenesis,track,and lowest center pressure densities)of Arctic cyclones are generally better in winter than in summer,and the models can simulate well that the number of external Arctic cyclones entering the Arctic region from the midlatitudes is more than the internal Arctic cyclones generated inside the Arctic region(60°‒90°N).Furthermore,we show that the capability of models to capture Arctic cyclones with a short lifespan(<3 d)is somewhat *** for the simulation of the minimum pressure of Arctic cyclones,the performance of high-resolution models is better than that of low-resolution *** simulation of Arctic cyclone radius is poor among all of the variables related to Arctic cyclones,and the observed trends of intensiti

关键词： CMIP6 Arctic cyclones Simulation capability assessment

Bidirectional Optimization Coupled Ligh tweight Net works for Efficient and Robust Multi-Person 2D Pose Estimation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2019年第3期34卷 522-536页

作者： Shnai Li zheng Fang Wen-Feng song ai-Min Hao Hong Qin State Key Laboratory of Virtual Reality Technology and Systems Beihang UniversityBeijing 100191China Beihang University Qingdao Research Institute Qingdao 266000China Department of Computer Science Stony Brook UniversityStony Brook 11790U.S.A.

For multi-person 2D pose estimation,current deep learning baised methods have exhibited impressive performance,but the trade-offs among efficiency,robustness,and accuracy in the existing approaches remain *** principle,bottom-up methods are superior to top-down methods in efficiency,but they perform worse in *** make full use of their respective advantages,in this paper we design a novel bidirectional optimization coupled lightweight network(BOCLN)architecture for efficient,robust,and general-purpose multi-person 2D(2-dimensional)pose estimation from natural *** the BOCLN framework,the bottom-up network focuses oil global features,while the top-down net work places emphasis on det ailed *** entire framework shares global features along the bottom-up data stream,while the top-down data stream aims to accelerate the accurate pose *** particular,to exploit the priors of human joints'relationship,we propose a probability limb heat map to represent the spatial context of the joints and guide the overall pose skeleton prediction,so that each person's pose estimation in cluttered scenes(involving crowd)could be as accurate and robust as ***,benefiting from the novel BOCLN architecture,the tinie-consuming refinement procedure could be much simplified to an efficient lightweight *** experiments and evaluations on public benchmarks have confirmed that our new method is more efficient and robust,yet still attain competitive accuracy performance compared with the state-of-the-art *** BOCLN shows even greater promise in online applications.

关键词： bidirectional optimization computer vision deep learning probability limb heat map 2D multi-person pose estimation

PIMD:An Integrative Approach for Drug Repositioning Using Multiple Characterization Fusion

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Genomics, Proteomics & Bioinformatics 2020年第5期18卷 565-581页

作者： song He Yuqi Wen Xiaoxi Yang zhen Liu Xinyu song Xin Huang Xiaochen Bo Department of Biotechnology Beijing Institute of Radiation MedicineBeijing 100850China

The accumulation of various types of drug informatics data and computational approaches for drug repositioning can accelerate pharmaceutical research and ***,the integration of multi-dimensional drug data for precision repositioning remains a pressing ***,we propose a systematic framework named PIMD to predict drug therapeutic properties by integrating multi-dimensional data for drug *** PIMD,drug similarity networks(DSNs)based on chemical,pharmacological,and clinical data are fused into an integrated DSN(iDSN)composed of many *** than simple fusion,PIMD offers a systematic way to annotate *** drugs within clusters and drug pairs with a high iDSN similarity score are therefore identified to predict novel therapeutic *** provides new insights into the universality,individuality,and complementarity of different drug properties by evaluating the contribution of each property *** test the performance of PIMD,we use chemical,pharmacological,and clinical properties to generate an *** of the contributions of each drug property indicate that this iDSN was driven by all data types and performs better than other *** the top 20 recommended drug pairs,7 drugs have been reported to be *** source code for PIMD is available at https://***/Sepstar/PIMD/.

关键词： Drug repositioning Drug similarity network Multiple characterization fusion Network pharmacology Drug discovery