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Improving maize residue cover estimation with the combined use of optical and SAR remote sensing images

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International Soil and Water Conservation Research 2024年第3期12卷 578-588页

作者： yiwei zhang Jia Du Northeast Institute of Geography and Agroecology CASChangchunJilin130102China

Conservation tillage is an important conservation measure for arable land in modern agricultural pro-duction,which plays an essential role in protecting black soil and improving the quality of arable *** estimation of maize residue cover(MRC)can be used to obtain the spatial distribution characteristics of conservation tillage,which is essential for government departments to promote conservation tillage technology and understand the implementation of *** this paper the southern part of the Songnen Plain was used as the study area,and Sentinel-2 MSI images and Sentinel-1 SAR images were used as data sources to correlate the spectral indices and radar backscatter coefficients with the field sampling data in the study *** MRC estimation model of the study area was constructed using the Random Forest(RF)model,the Multiple Linear Stepwise Regression(MLSR)model,and Back Propagation Neural Network(BPNN)model,*** results of the study showed that the correlation coefficients of normalized difference tillage index(NDTI),simple tillage index(STI),normalized difference index(NDI5),NDI7,shortwave infrared normalized difference residue index(SINDRI),normalized difference senescent vegetation index(NDSVI),normalized difference residue index 2(NDRI2),NDRI3,NDRI4,NDR15,NDRI6,NDRI7,NDR18,NDRI9,and MRC in the study area were greater than 0.4,and the correlation coefficients were higher for NDTI and STI,which reached 0.861 and 0.860,*** correlation coefficient between W and MRC was 0.56 and between VH and MRC was *** used MLSR,RF,and BPNN methods in combination with Sentinel-2 MSI images and Sentinel-1 SAR images for MRC *** synergistic use of Sentinel-2 MSI images and Sentinel-1 SAR images helped to improve the accuracy of the MRC estimation models and the correlation coefficient R2 of all three models to greater than *** on the statistical analysis of remote sensing estimation results,we found that the average value of the M

关键词： Maize residue cover Sentinel-1 Sentinel-2ML SRBPNNRF

快速气相色谱法测定汽油单体烃组成及多项物性预测模型的建立

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石油炼制与化工 2025年第1期56卷 172-180页

作者：李长秀王亚敏张祎玮王征钱钦中石化石油化工科学研究院有限公司北京100083

建立了采用40 m×0.10 mm×0.20μm超细内径非极性色谱柱、氢气作载气的快速分析汽油馏分单体烃组成的方法(简称快速单体烃分析方法)。对于催化裂化汽油C_(3)~C_(12)组分可以得到367个色谱峰,正十二烷的保留时间为30.1 min。同一样品重... 详细信息

建立了采用40 m×0.10 mm×0.20μm超细内径非极性色谱柱、氢气作载气的快速分析汽油馏分单体烃组成的方法(简称快速单体烃分析方法)。对于催化裂化汽油C_(3)~C_(12)组分可以得到367个色谱峰,正十二烷的保留时间为30.1 min。同一样品重复测定3次的结果显示组分保留时间极差小于0.02 min,保留指数极差小于0.50。对于质量分数大于0.5%的单体烃组分,含量测定结果的相对标准偏差小于6%;对于质量分数小于0.5%的单体烃组分,含量测定结果的相对标准偏差小于10%。建立了根据汽油单体烃分析结果计算汽油的密度、饱和蒸气压、折射率、碳氢元素含量、平均相对分子质量、溴值的修正计算模型。根据修正模型计算样品的密度、折射率和饱和蒸气压,计算结果与实测结果有较好的一致性。根据快速单体烃分析方法的测定结果和采用50 m×0.20 mm×0.50μm非极性色谱柱的常规单体烃分析方法的测定结果计算多项物性参数,两种方法下的计算结果一致,说明建立的计算模型也适用于采用快速单体烃分析方法的测定结果计算样品的多项物性参数。

关键词：汽油单体烃快速分析气相色谱物性参数

A chaos-based image encryption algorithm using alternate structure

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Science in China(Series F) 2007年第3期50卷 334-341页

作者： zhang yiwei WANG YuMin SHEN XuBang Xi'an Microelectronics Technology Institute Xi'an 710054 China National Key Lab of Integrated Service Networks Xidian University Xi'an 710071 China

Combined with two chaotic maps, a novel alternate structure is applied to image cryptosystem. In proposed algorithm, a general cat-map is used for permutation and diffusion, as well as the OCML （one-way coupled map lattice）, which is applied for substitution. These two methods are operated alternately in every round of encryption process, where two subkeys employed in different chaotic maps are generated through the masterkey spreading. Decryption has the same structure with the encryption algorithm, but the masterkey in each round should be reversely ordered in decryption. The cryptanalysis shows that the proposed algorithm bears good immunities to many forms of attacks. Moreover, the algorithm features high execution speed and compact program, which is suitable for various software and hardware applications.

关键词： chaotic encryption general cat-map OCML image encryption

Effect of aluminum modification on catalytic properties of PtSn-based catalysts supported on SBA-15 for propane dehydrogenation

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Journal of Natural Gas Chemistry 2012年第2期21卷 207-214页

作者： Yongzheng Duan Yuming Zhou yiwei zhang Xiaoli Sheng Shijian Zhou Zewu zhang School of Chemistry and Chemical Engineering Southeast UniversityNanjing 211189JiangshuChina

The catalytic properties of PtSn-based catalysts supported on siliceous SBA-15 and Al-modified SBA-15, such as Al-incorporated SBA-15 （AlSBA-15） and alumina-modified SBA-15 （Al2O3/SBA-15）, for propane dehydrogenation were investigated. Al2O3/SBA-15 was prepared either by an impregnation method using aluminum nitrate aqueous solution, or by the treatment of SBA-15 with a Al（OC3H7）3 solution in anhydrous toluene. N2-physisorption, FT-IR spectroscopy, solid-state 27Al MAS NMR spectroscopy, hydrogen chemisorption, XRF, NH3 temperature-programmed desorption, X-ray photoelectron spectroscopy and TPO were used to characterize these samples. Among these catalysts, the PtSn-based catalyst supported on Al2O3/SBA-15, which was grafted with Al（OC3H7）3, exhibited the best catalytic performance in terms of activity and stability The possible reason was due to the high Pt metal dispersion and/or the strong interactions among Pt, Sn, and the support.

关键词： propane dehydrogenation Pt SBA-15 aluminum modification

Early monitoring of response to antimetabolic treatment of gemcitabine:A comparison of ^(18)F-FLT and ^(18)F-FDG uptake in Patu 8988 human pancreatic carcinoma cells

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Nuclear Science and Techniques 2011年第5期22卷 293-298页

作者： DENG Shengming zhang Bin WU yiwei zhang Wei Department of Nuclear Medicine No.1 Hospital Affiliated to Sooehow University Suzhou 215006 China

It is essential to predict the treatment efficacy of pancreatic carcinoma *** purpose of this study was to examine whether ^(18)F-FDG(2'-deoxy-2'-[^(18)F]fiuoro-D-glucose) or ^(18)F-FLT(3'-deoxy-3'-^(18)F-fluorothymidine) PET can be used for chemosensitivity testing by investigating the binding characteristic of ^(18)F-FDG or ^(18)F-FLT with Patu 8988 human pancreatic carcinoma cell and the influence of gemcitabine in the uptake of ^(18)F-FDG or ^(18)F-FLT on Patu *** the conditions of 1×10~6 cells,3.7 kBq ^(18)F-FDG or ^(18)F-FLT,and incubation at 37℃for 100 min,the cell uptake of ^(18)F-FDG and ^(18)F-FLT was(60.60±3.05)%and(50.57±2.81)%,*** was a significant decrease in TKl-LI(thymidine kinase 1 labeling index) 24 h after administration of *** uptakes of ^(18)F-FDG and ^(18)F-FLT were negatively correlated with the doses of gemcitabine(r= -0.928 for ^(18)F-FDG,r= -0.876 for ^(18)F-FLT,P<0.01).When same doses of gemcitabine were administered,the ^(18)F-FLT uptake inhibition rate was significantly higher than that of ^(18)F-FDG(P<0.01).These results indicate that the response to gemcitabine could be predicted as early as 24 h by ^(18)F-FDG or ^(18)F-FLT PET scans.^(18)F-FLT is more sensitive than ^(18)F-FDG to predict the response to therapy.

关键词：细胞摄取早期预测治疗效果 FDG 癌细胞胰腺癌 LSF 药物敏感性

A Manta Ray-Inspired Biosyncretic Robot with Stable Controllability by Dynamic Electric Stimulation

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Cyborg and Bionic Systems 2022年第1期2022卷 314-326页

作者： Chuang zhang yiwei zhang Wenxue Wang Ning Xi Lianqing Liu State Key Laboratory of Robotics Shenyang Inst itute of AutomationChinese Academy of SciencesShenyang 110016China Institutes for Robotics and Intelligent Manufacturing Chinese Academy of SciencesShenyang 110169China School of Automation and Electrical Engineering Shenyang Ligong University Shenyang 110159China Emerging Technologies Institute Department of Industrial Manufacturing Systems Engineering University of Hong KongPokfulamChina

Biosyncretic robots,which are new nature-based robots in addition to bionic robots,that utilize biological materials to realize their core function,have been supposed to further promote the progress in *** as the main operation mechanism relates to the robotic overall ***,biosyncretic robots actuated by living biological actuators have attracted increasing ***,innovative propelling modes and control methods are still necessary for the further development of controllable motion performance of biosyncretic *** this work,a muscle tissue-based biosyncretic swimmer with a manta *** propelling mode has been *** is more,to improve the stable controllability of the biosyncretic swimmer,a dynamic control method based on circularly distributed multiple electrodes(CDME)has been *** this method,the direction of the electric field generated by the CDME could be real-time controlled to be parallel with the adtuation tissue of the dynamic ***,the instability of the tissue actuation induced by the dynamic included angle between the tissue axis and electric field direction could be ***,the biosyncretic robot has demonstrated stable,controllable,and efective swimming,by adjusting the electric stimulation pulse direction,amplitude,and *** work may be beneficial for not only the development of biosyncretic robots but also other related studies including bionic design of soft robots and muscle tissue engineering.

关键词： Robot robot Dynamic

Bi/Bi_(3)Se_(4) nanoparticles embedded in hollow porous carbon nanorod:High rate capability material for potassium-ion batteries

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Journal of Energy Chemistry 2023年第6期81卷 462-471,I0011页

作者： Zhisong Chen Yuanji Wu Xi Liu yiwei zhang Lichun Yang Hongyan Li Department of Materials Science and Engineering College of Chemistry and Materials ScienceJinan UniversityGuangzhou 510632GuangdongChina School of Materials Science and Engineering and Guangdong Provincial Key Laboratory of Advanced Energy Storage MaterialsSouth China University of TechnologyGuangzhou 510640GuangdongChina

Considering their superior theoretical capacity and low voltage plateau,bismuth(Bi)-based materials are being widely explored for application in potassium-ion batteries(PIBs).Unfortunately,pure Bi and Bibased compounds suffer from severe electrochemical polarization,agglomeration,and dramatic volume *** develop an advanced bismuth-based anode material with high reactivity and durability,in this work,the pyrolysis of Bi-based metal-organic frameworks and in-situ selenization techniques have been successfully used to produce a Bi-based composite with high capacity and unique structure,in which Bi/Bi_(3)Se_(4)nanoparticles are encapsulated in carbon nanorods(Bi/Bi_(3)Se_(4)@CNR).Applied as the anode material of PIBs,the Bi/Bi_(3)Se_(4)@CNR displays fast potassium storage capability with 307.5 m A h g^(-1)at 20 A g^(-1)and durable cycle performance of 2000 cycles at 5 A g^(-1).Notably,the Bi/Bi_(3)Se_(4)@CNR also showed long cycle stability over 1600 cycles when working in a full cell system with potassium vanadate as the cathode material,which further demonstrates its promising potential in the field of ***,the dual potassium storage mechanism of the Bi/Bi_(3)Se_(4)@CNR based on conversion and alloying reaction has also been revealed by in-situ X-ray diffraction.

关键词： Bi_(3)Se_(4) Potassium ion battery Hollow porous carbon rod Conversion-alloying mechanism Bi MOF

Differences in Atmospheric Heat Source between the Tibetan Plateau–South Asia Region and the Southern Indian Ocean and Their Impacts on the Indian Summer Monsoon Outbreak

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Journal of Meteorological Research 2017年第3期31卷 540-554页

作者： yiwei zhang Guangzhou FAN Wei HUA Yongli zhang Bingyun WANG Xin LAI College of Atmospheric Sciences Chengdu University of Information Technology/Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science &Technology

In this paper, the NCEP-NCAR daily reanalysis data are used to investigate the characteristics of the atmospheric heat source/sink （AHSS） over South Asia （SA） and southern Indian Ocean （SIO）. The thermal differences between these two regions and their influence on the outbreak of the Indian summer monsoon （ISM） are explored. Composite analysis and correlation analysis are applied. The results indicate that the intraseasonal variability of AHSS is signi- ficant in SA but insignificant in the SIO. Large inland areas in the Northern Hemisphere still behave as a heat sink in March, similar to the situation in winter. Significant differences are found in the distribution of AHSS between the ocean and land, with distinct land-ocean thermal contrast in April, and the pattern presents in the transitional period right before the ISM onset. In May, strong heat centers appear over the areas from the Indochina Peninsula to the Bay of Bengal and south of the Tibetan Plateau （TP）, which is a typical pattern of AHSS distribution during the monsoon season. The timing of SA-SIO thermal difference turning positive is about 15 pentads in advance of the onset of the ISM. Then, after the thermal differences have turned positive, a pre-monsoon meridional circulation cell develops due to the near-surface heat center and the negative thermal contrast center, after which the meridional circulation of the ISM gradually establishes. In years of early （late） conversion of the SASIO thermal difference turning from neg- ative to positive, the AHSS at all levels over the TP and SIO converts later （earlier） than normal and the establish- ment of the ascending and descending branches of the ISM＇s meridional circulation is later （earlier） too. Meanwhile, the establishment of the South Asian high over the TP is later （earlier） than normal and the conversion of the Mas- carene high from winter to summer mode occurs anomalously late （early）. As a result, the onset of the ISM is later （earlier） than nor

关键词： Tibetan Plateau South Asia southern Indian Ocean atmospheric heat source Indian summer monsoon,land-ocean thermal contrast

Influence of Alumina Content on Catalytic Performance of PtSn/Al_2O_3/SBA-15 Catalysts for Propane Dehydrogenation

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China Petroleum Processing & Petrochemical Technology 2012年第4期14卷 9-16页

作者： zhang Peixin Zhou Yuming Duan Yongzheng zhang yiwei Sheng Xiaoli School of Chemistry and Chemical Engineering Southeast University Geological Survey of Jiangsu Province

The alumina-modified SBA-15 （A12OJSBA-15） zeolite was prepared in a non-aqueous system by using toluene as the solvent, and was used to support the PtSn-based catalyst for propane dehydrogenation. The BET surface area mea- surements, hydrogen chemisorption, FT-IR spectroscopy, NH3-TPD, XPS and TPO techniques were used to characterize the catalysts. Test results showed that the addition of alumina not only could modify the acid function of the support but also the structure of the metallic phase, thus affecting their catalytic properties. Among these catalysts studied, the PtSn/AI203 （5%）/ SBA-15 catalyst exhibited a best catalytic performance in terms of propane conversion and selectivity to propene. The high catalytic performance might be attributed to the relatively good Pt metal dispersion and/or the strong interaction between Pt and Sn species.

关键词： SBA- 15 A1203 propane dehydrogenation propene Pt