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Depth recovery for unstructured farmland road image using an improved SIFT algorithm

International Journal of Agricultural and Biological Engineering 2019年第4期12卷 141-147页

作者： lijian Yao Dong Hu Zidong Yang Haibin Li Mengbo Qian School of Engineering Zhejiang A&F UniversityHangzhou 311300China

Road visual navigation relies on accurate road *** study was aimed at proposing an improved scale-invariant feature transform(SIFT)algorithm for recovering depth information from farmland road images,which would provide a reliable path for visual *** mean image of pixel value in five channels(R,G,B,S and V)were treated as the inspected image and the feature points of the inspected image were extracted by the Canny algorithm,for achieving precise location of the feature points and ensuring the uniformity and density of the feature *** mean value of the pixels in 5×5 neighborhood around the feature point at an interval of 45ºin eight directions was then treated as the feature vector,and the differences of the feature vectors were calculated for preliminary matching of the left and right image feature *** order to achieve the depth information of farmland road images,the energy method of feature points was used for eliminating the mismatched *** with a binocular stereo vision system were conducted and the results showed that the matching accuracy and time consuming for depth recovery when using the improved SIFT algorithm were 96.48%and 5.6 s,respectively,with the accuracy for depth recovery of-7.17%-2.97%in a certain sight *** mean uniformity,time consuming and matching accuracy for all the 60 images under various climates and road conditions were 50%-70%,5.0-6.5 s,and higher than 88%,respectively,indicating that performance for achieving the feature points(e.g.,uniformity,matching accuracy,and algorithm real-time)of the improved SIFT algorithm were superior to that of conventional SIFT *** study provides an important reference for navigation technology of agricultural equipment based on machine vision.

关键词： scale-invariant feature transform(sift) feature matching canny operator energy method of feature point farmland road depth recovery visual navigation

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High performance IEICO-4F/WSe_(2)heterojunction photodetector based on photoluminescence quenching behavior

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Nano Research 2022年第9期15卷 8595-8602页

作者： Qinghai Zhu Yexin Chen Tianyi Chen lijian Zuo Yijun Sun Rong Wang Mingsheng Xu School of Micro-Nano Electronics State Key Laboratory of Silicon MaterialsZhejiang UniversityHangzhou 310027China Department of Polymer Science and Engineering State Key Laboratory of Silicon MaterialsZhejiang UniversityHangzhou 310027China College of Information Science&Electronic Engineering Zhejiang University38 Zheda RoadHangzhou 310027China ZJU Hangzhou Global Sci&Technol Innovation Centre Adv Semiconductor Research InstituteHangzhou 311215China

Heterostructure is the basic building block for functional optoelectronic *** consisting of two-dimensional(2D)transition metal dichalcogenides(TMDs)and organic semiconductors are currently attracting great interest for highperformance ***,how to design heterostructure for highly efficient optoelectronic devices remains a big *** we design high-performance organic semiconductor/WSe_(2)heterostructure photodetectors by tailoring the charge transfer effect between 2,2ʹ-((2Z,2ʹZ)-(((4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydros-indaceno[1,2-b:5,6-bʹ]dithiophene-2,7-diyl)bis(4-((2-ethylhexyl)oxy)thiophene-5,2-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(IEICO-4F)organic semiconductors with various thicknesses and monolayer WSe_(2).With the increase of IEICO-4F layer thickness,the photoluminescence(PL)characteristics of WSe_(2)could be completely quenched due to the charge transfer from the lowest unoccupied molecular orbital(LUMO)level of IEICO-4F to the conduction band minimum(CBM)of WSe_(2).Benefiting from the exquisite charge transfer behavior,the IEICO-4F/WSe_(2)heterojunction photodetector with optimized 6.0-nm thick IEICO-4F shows high performance including the responsivity of 8.32 A/W and specific detectivity of 4.65×10^(11)Jones at incident light of 808 *** work demonstrates a simple approach based on PL characteristics to design high-performance IEICO-4F/WSe_(2)heterojunction,thus paving the way for the development of excellent optoelectronic devices based on organic/TMD heterostructures.

关键词： tungsten diselenide organic semiconductor type-II heterojunction photoluminescence quenching photodetector

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Wireless positioning and path tracking for a mobile platform in greenhouse

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International Journal of Agricultural and Biological Engineering 2021年第1期14卷 216-223页

作者： lijian Yao Dong Hu Chao Zhao Zidong Yang Zhao Zhang School of Engineering Zhejiang A&F UniversityHangzhou 311300China Department of Agricultural and Biosystems Engineering North Dakota State UniversityFargoND 58102USA

In order to realize intelligent greenhouse,an automatic navigation method for a mobile platform based on ultra-wideband(UWB)positioning technology was proposed and validated in this *** time difference of arrival(TDOA)approach was used to monitor and track the UWB positioning to obtain the localization information of the mobile platform working in a *** applying polynomial fitting for positioning error correction,the system accuracy was within 5 mm.A fuzzy controller model was constructed by incorporating the lateral and heading deviations as input variables and the steering angle of front wheel as the output variable.A fuzzy rule was established based on domain knowledge,as well as the steering angle of front wheel offline query table,which was applied to alleviate the calculative load of the *** results confirmed that the automatic navigation method proposed in this study performed satisfactorily,with a steady-state error ranging from 41 mm to 79 mm when tracking straight line,and an average error of 185 mm and an average maximum error of 532 mm when tracking *** addition,the maximum error occurred at the polygonal corner which could meet the needs of driving on the narrow road in the *** method proposed in this study provides a new systematic approach for the research of greenhouse automatic navigation.

关键词： wireless positioning ultra-wideband path tracking positioning error correction fuzzy control query table mobile platform greenhouse

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Degree of Brine Evaporation and Origin of the Mengyejing Potash Deposit：Evidence from Fluid Inclusions in Halite

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Acta Geologica Sinica(English Edition) 2017年第1期91卷 175-185页

作者： SHEN lijian LIU Chenglin WANG Licheng HU Yufei HU Mingyue FENG Yuexing MLR Key Laboratory of Metallogeny and Mineral Assessment Institute of Mineral Resources Chinese Academy of Geological Sciences Beijing 100037 China National Research Center for Geoanalysis Beijing 100037 China Radiogenic Isotope Facility School of Earth Sciences the University of Queensland Brisbane 4072 QLDAustralia

The Mengyejing potash deposit is located in the southern port of the Simao Basin, Yunnan Province, and is hosted in mid-Cretaceous strata. The chemical compositions of fluid inclusions in halite crystals, collected from the level-610 adit in the deposit, were analysed by laser ablation inductively coupled plasma mass spectrometry（LA-ICP-MS）. The results show that the brine is of the Na-K-Mg-Ca-Cl type and has K concentrations that are distinctly higher than those of Mg and Ca, unlike normal brines associated with Cretaceous halite. The high K concentrations indicate that the degree of evaporation of the ancient Mengyejing saline lake was very high, reaching the sylvite deposition stage but rarely reaching the carnallite deposition stage. The trajectory of the H and O isotopic compositions of the brines in the halite-hosted fluid inclusions corresponds to intense evaporation, indicating that the net evaporation exceeded the net inflow of brines. These brine compositions in halite-hosted fluid inclusions were likely formed by the dissolution of previously deposited K-bearing minerals by fresh continental and/or seawater, forming a type of modified seawater, with deep hydrothermal fluids potentially supplying additional potassium. The basin likely experienced multiple seawater incursion, dissolution and redeposition events in a high-temperature environment with high evaporation rates.

关键词： Cretaceous halite fluid inclusions H and O isotopic compositions brine chemical compositions Mengyejing potash deposit Yunnan Province

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Influence of micro-water on AC breakdown characteristics of C_(4)F_(7)N/CO_(2)gas mixture under non-uniform electric field

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High Voltage 2022年第6期7卷 1059-1068页

作者： Yuan Yang Keli Gao Jiangang Bi lijian Ding Shuai Yuan Guangzhen Wang School of Electric Engineering and Automation Hefei University of TechnologyAnhui ProvinceAnhui ProvinceChina State Key Laboratory of Power Grid Environmental Protection China Electric Power Research InstituteBeijingChina

The application of eco-friendly C_(4)F_(7)N/CO_(2)gas mixture has become a hot topic in the power *** obtain the influence law of micro-water on the AC insulation characteristics of C_(4)F_(7)N/CO_(2)gas mixture,breakdown tests were carried out under different non-uniform electric fields and micro-water volume *** the gap distance of 1 mm and the electric field non-uniform coefficient less than 4.42,the breakdown voltage is positively correlated with gas *** the gap distance of 6 mm and the electric field non-uniform coefficient of 9.28,the breakdown voltage shows a typical N-type change trend with the increase of gas *** the gap distance of 9 mm and the electric field non-uniform coefficient up to 16.45,the breakdown voltage shows a typical N-type change trend with the increase of gas ***-water has a negative effect on breakdown voltage under different electric fields,meanwhile the breakdown voltage of slightly non-uniform electric field is greatly affected by micro-water,and the influence of micro-water on breakdown voltage is different under different gas ***,the influence of operating gas pressure and slightly non-uniform electric field should be considered when the micro-water control index of C_(4)F_(7)N/CO_(2)gas mixture insulated equipment is formulated.

关键词： breakdown uniform mixture

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Transformation and Field-Induced Strains in as-Cast Ni-Mn-Ga Alloy

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Journal of Iron and Steel Research International 2004年第6期11卷 52-56页

作者： ZHAOWei-ren lijian-liang QIYan ZHANGYang-huan WANGXin-lin YUYuan-jun ShantouUniversity Shantou515063China CentralIronandSteelResearchInstitute Beijing100081China ZhejiangNormalUniversity Jinhua321004China

The characteristics of the strains induced by transformation and magnetic field in ascast Ni-Mn-Ga alloy were systematically *** is found that internal stress and texture introduced during casting bring the anisotropy of temperature-induced ***,no anisotropy of field-induced strains is induced,and the internal stress and the texture modulate only the temperature dependence of field-induced *** retardance of field-induced strains was observed,which indicates the rearrangement of martensitic variants as a competition process between the stress energy and Zeeman *** non-continuous field dependence of strain indicates the unstable microstructure during martensitic transformation.

关键词： magnetic ordered material intermetallics casting strain

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The Present Situation and Prospect of the Study on Locoweed in China

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Agricultural Sciences in China 2003年第6期2卷 687-698页

作者： lijian-ke WANGJian-hua CollegeofLifeScience ShaanaciNormalUniversityXi‘an710062P.R.China CollegeofAnimalScienceandTechnology NorthwestSci-TechUniversityofAgricultureandForestryYangling712100P.R.China

Locoweed is one of main poisonous plants in the world, and also is the most important toxic plant in grassland of China. The distribution range of the locoweed is extending continuously and it has formed or is coming into dominant species gradually in some areas in recent years, which cause the retrogressive succession and grazer poisoning and died in rangeland. Locoweed seriously threatened the grassland agriculture and made typical 'ecology-economic sick' in above district. Based on the investigation, research, prevention and cure practice to the locoweed for more than ten years, this paper reviewed the present situation and prospect of the studies on the locoweed in China, which include the researches of it's biological characteristics, distribution, ecological environment, harmfulness, prevention, weeding, utilization and ecological control etc.

关键词： Locoweed (Oxytropis sp. and Astragalus L.). Harmfulness Prevention and control

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Numerical Simulation of Blood Flow in Aorta with Dilation:A Comparison between Laminar and LES Modeling Methods

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Computer Modeling in Engineering & Sciences 2020年第8期124卷 509-526页

作者： lijian Xu Tianyang Yang Lekang Yin Ye Kong Yuri Vassilevski Fuyou Liang School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Shanghai Chest Hospital Shanghai Jiao Tong UniversityShanghai200030China Zhongshan Hospital Fudan UniversityShanghai200032China Marchuk Institute of Numerical Mathematics Russian Academy of SciencesMoscow119333Russia Institute for Personalized Medicine Sechenov UniversityMoscow119991Russia Key Laboratory of Hydrodynamics(Ministry of Education) Shanghai Jiao Tong UniversityShanghai200240China

Computational modeling methods have been increasingly employed to quantify aortic hemodynamic parameters that are challenging to in vivo measurements but important for the diagnosis/treatment of aortic *** the presence of turbulence-like behaviors of blood flow in normal or diseased aorta has long been confirmed,the majority of existing computational model studies adopted the laminar flow assumption(LFA)in the treatment of sub-grid flow *** far,it remains unclear whether LFA would significantly compromise the reliability of hemodynamic *** the present study,we addressed the issue in the context of a specific aortopathy,namely aortic dilation,which is usually accompanied by disturbed flow *** patient-specific aortas with treated/untreated dilation of the ascending segment were investigated,and their geometrical models were reconstructed from computed tomography angiographic images,with the boundary conditions being prescribed based on flow velocity information measured in vivo with the phase contrast magnetic resonance imaging *** the modeling of blood flow,apart from the traditional LFA-based method in which sub-grid flow dynamics is ignored,the large eddy simulation(LES)method capable of incorporating the dissipative energy loss induced by turbulent eddies at the sub-grid level,was adopted and taken as a reference for examining the performance of the LFA-based *** results showed that the simulated large-scale flow patterns with the two methods had high similarity,both agreeing well with in vivo measurements,although locally large between-method discrepancies in computed hemodynamic quantities existed in regions with high intensity of flow ***,a switch from the LES to the LFAbased modeling method led to mild(<6%)changes in computed space-averaged wall shear stress metrics(i.e.,SA-TAWSS,SA-OSI)in the ascending aortic segment where intensive vortex evolution accompanied by high stat

关键词： Blood flow aortic dilation computational modeling turbulence laminar flow assumption large eddy simulation

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Preventive and therapeutic effectiveness of Sanfu acupoint herbal patching for chronic obstructive pulmonary disease at stable stages:a systematic review and Meta-analysis

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Journal of Traditional Chinese Medicine 2020年第4期40卷 530-549页

作者： Pang lijian Zhang Haoyang Lu Xiaodong Liu Jianping Liu Chuang Lu Ling Beijing University of Chinese Medicine Beijing 100029China Affiliated Hospital of Liaoning University of Traditional Chinese Medicine Shenyang 110032China Liaoning University of Traditional Chinese Medicine Shenyang 110033China Center for Evidence Based Chinese Medicine Beijing University of Chinese MedicineBeijing 100029China

OBJECTIVE:To evaluate the preventive and therapeutic effects of Sanfu acupoint herbal patching(SAHP)in adjuvant treatment in patients with stable chronic obstructive pulmonary disease(COPD).METHODS:We had searched eight electronic databases and six major trial registries from their inception to July 2017 for randomized controlled trials(RCTs).We utilized RevMan 5.3 to evaluate the methodological quality and to perform data ***:A total of 28 RCTs involving 1615 records were included in the descriptive analysis,and 25 RCTs were performed for *** function such as forced vital capacity rate of one second FEV1/predicted%,forced vital capacity(FVC)%found no significant *** results of Meta-analysis showed that SAHP plus conventional therapy(CT)in the treatment of stable COPD were better than CT,in second sessions'data of FEV1,in third sessions'data of FEV1/FVC,in three sessions'data of SGRQ,in third session's data of Modified Medical Research Council and *** symptoms of SAHP's adverse reactions seem to be mild and the incidence of that seems to be *** analysis shows that SAHP with CT seems to improve clinical effective rate and had a certain preventive effect on acute exacerbation of COPD,which the curative effect may be better with the increase of treatment ***:SAHP with CT appears to be more effective than CT or CT plus placebo only on improving the quality of life,but the effect on lung function is not *** clinical effective rate and preventive effect is *** with CT may be used in any Grade to safely treat patients with stable *** more exactly clinical effect still needs to be proved by more high-quality,large sampling,multilingual RCTs.

关键词： Pulmonary disease,chronic obstructive Acupoint sticking therapy Randomized controlled trials Systematic review

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Review of the decomposition characteristics of eco-friendly insulation gas

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High Voltage 2021年第5期6卷 733-749页

作者： Yuan Yang Keli Gao lijian Ding Jiangang Bi Shuai Yuan Xianglian Yan School of Electrical Engineering and Automation Hefei University of TechnologyAnhui ProvinceChina State Key Laboratory of Power Grid Environmental Protection China Electric Power Research InstituteBeijingChina

As one of the major concerns of climate change,identifying a proper eco‐friendly insulation gas for replacing sulphur hexafluoride(SF_(6))becomes a prominent research topic in recent years.c-C_(4)F_(8),CF_(3)I,C_(5)F_(10O),C_(6)F_(12O)and C4F7N are some potential al-ternatives that are proved to have excellent characteristics,including high insulation strengths and low Global Warming Potentials(GWPs).Beyond these key factors,the decomposition products of these alternatives are closely related to the gases'insulation performance,as well as the safety of operators and the compatibility with other *** addition,the type and content of decomposition products can be used for fault ***,a number of studies were carried out to reveal the decomposition mechanism of these alternative gases,and then to explore the gases'application feasibility and *** recent advances obtained in these studies,including theoretical calcu-lation methods,detection of gas decomposition products,decomposition mechanism are reviewed,and some perspectives for future works are *** is concluded that the phenomenon of solid matter precipitation in c-C_(4)F_(8)and CF_(3)I gas decomposition cannot be ignored and that more research is needed to reveal the influence of buffer gases,micro‐aerobic,micro‐water and other impurities on the gas decomposition process.

关键词： insulation gases characteristics

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