检索结果-南通市图书馆

Design and experimental validation of sliding knife notch-type disc opener for a no-till combine harvester cum seed drill

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2018年第4期11卷 96-103页

作者： Kuan Qin weimin ding Fiaz Ahmad Zhichao Fang College of Engineering Nanjing Agricultural UniversityJiangsu ProvinceNanjing 210031China Department of Agricultural Engineering Bahauddin Zakariya UniversityMultanPakistan

One major constraint in developing a combine harvester cum seed drill(CHCSD)is the limited space available for the attachment of no-till furrow *** the straw stubble cutting and furrow opening performance of small-sized disc furrow openers is critically important for the development and the optimization of the no-till seeding assemblies.A set of down-scaled sliding knife notch-type disc opener(SKO),modified notch-type disc opener(MNO)and smooth-type disc opener(SDO),with upper size limit of 160 mm,were designed and fabricated for field *** results show that for small-sized disc furrow openers of the same type,a larger disc diameter yields a greater furrow depth and *** small-sized disc furrow openers with an identical diameter,SKOs yield a greater furrow depth and width than MNOs,with SDOs yielding the lowest *** measured furrow depth and width for an SKO with diameter of 160 mm are 3.52 cm and 3.56 cm,respectively,meeting the no-tillage furrowing requirements for a *** highest stubble cover rate of 62.5%is obtained for the SKO with diameter of 160 ***,this opener has greater ability to remove stubble from the furrow and seeding band than the other ***,experimental results of the stubble cutting rates confirm that,for irregularly placed straw and residue,the stubble cutting rate of the SKO with diameter of 160 mm is the highest at 61.7%.

关键词： no-tillage small-sized disc furrow opener furrow type stubble removal

Droplet size and spray pattern characteristics of PWM-based continuously variable spray

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2009年第1期2卷 8-18页

作者： Deng Wei He Xiongkui ding weimin College of Science China Agricultural UniversityBeijing 100193China College of Engineering Nanjing Agricultural UniversityNanjing 210031China

A Pulse-Width-Modulation-based(PWM-based)continuously variable sprayer was developed using a proportional regulating solenoid *** flow-rate was obtained by varying the duty cycle of the actuating signal with 24 kHz ***-rate regulating ranges of the PWM-based continuously variable spray(*** turndown ratio responding to 100%-40%duty cycle)are 7.14:1,3.57:1,and 3.70:1 for flat-fan,hollow-cone and solid-cone nozzles,*** purpose of the study was to evaluate the PWM-based continuously variable *** method was to quantify the effects of flow-rate control on spray characteristics in terms of droplet size spectra,spray distribution patterns,and spray angle for flat-fan,hollow-cone,solid-cone *** all nozzles tested,spray distribution concentrated on the center of the spray field with the decrease of *** the spray shape is still *** sensitivities of the spray angles to flow-rate were 0.83,0.67,and 0.58(o)/%respectively for flat-fan,hollow-cone and solid-cone *** with the sensitivities of spray angle for PWM-based intermittent variable spray,they are somewhat *** flow-rate was reduced from the maximum(100%flow-rate)to the minimum controllable rate,the observed median diameter of spray droplets decreased by 5.4%,9.8%,and 9.9%for flat-fan,hollow-cone and solid-cone nozzles,*** indicates that spray droplet size was affected slightly by flow-rate control.

关键词： Pulse Width Modulation(PWM) continuously variable spray droplet size spray distribution pattern spray angle

Design and test of a novel crawler-type multi-channel air-assisted orchard sprayer

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2020年第6期13卷 60-67页

作者： Wei Qiu Xiaolong Li Chongchong Li weimin ding Xiaolan Lv Yande Liu College of Engineering Nanjing Agricultural UniversityNanjing 210031China Jiangsu Academy of Agricultural Sciences Nanjing 210000China Co-Innovation Center of the Intelligent Management and Equipment for Orchard on the Hilly Land in South China Nanchang 330013China

In order to solve the problem of poor traveling stability and excessive pesticide application during plant protection operations in hilly orchards,a novel crawler-type multi-channel air-assisted sprayer that is particularly appropriate for hilly orchards was designed in this *** anti-rolling requirements and the orchard environment in hilly areas,this study selected limits for uphill and downhill rolling angles as well as the transverse rolling angle as the evaluation indexes for determining both the layout and parameter settings of the *** to freely submerged jets and the requirements in plant protection operation,a multi-channel air-assisted system was *** test results showed that the anti-rolling performance and the designed air-assisted system were *** 2 m from the longitudinal center plane of the sprayer,the airflow exhibited wavy distribution patterns under different parameter combinations since the four streams of the airflow were not thoroughly intersected and *** 3 m from the longitudinal center plane of the sprayer,the jet was ejected at great velocity but underwent rapid attenuation;the airflow velocity in most areas barely satisfied the requirements for plant protection *** addition,different air outlet layout schemes led to significant differences in the spatial distribution of the airflow *** with a traditional air-assisted sprayer,using the developed multi-channel air-assisted sprayer enhanced the droplet coverage uniformity by 19.4%,and the mean droplet deposition in the front,middle,and rear of the canopy was enhanced by 32.9%,50.3%,and 78.1%,respectively,while reducing ground deposition and air drift by 26.8%.

关键词： fan dual-flow-channel plant protection air-assisted test

Tilting stability analysis and experiment of the 3-DOF lifting platform for hilly orchards

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2018年第6期11卷 73-80页

作者： Zhenhua Duan Wei Qiu weimin ding Yande Liu Yuping Ouyang Liang Huang College of Engineering Nanjing Agricultural UniversityNanjing 210031China Co-Innovation Center of the Intelligent Management and Equipment for Orchard on the Hilly Land in South China Nanchang330013China

An orchard-lifting platform is a type of mechanical equipment to assist growers in fruit picking,fruit tree pruning,flower thinning,and other *** its operational processes,the tilting stability directly affects the operational safety and adaptability under complex terrain conditions,while critical tilting angle is an important criterion to evaluate the tilting *** on the structure and the operating characteristics of the three degree of freedom(3-DOF)lifting platform for hilly orchards,the tilting stability was analyzed in different parked states,and the theoretical expressions of critical tilting angle were obtained;in the theoretical expressions,the influencing factors on tilting stability were determined as the parked positionβ1,the manned worktable rotary positionβ2,the lifting height h,and the load *** on the multi-body dynamics principle,the tilting stability simulation was carried *** relative error of tilting angles was approximately 4.6%between simulation and tilting verification experiment,which indicated that the results of tilting stability simulation were ***,the multi-body dynamics simulation was used for further clarifying the influencing factors on tilting stability.A virtual orthogonal test was designed,and the results showed that critical tilting angle ranged from 20°to 44°when the factors were at different values,which indicated that the 3-DOF lifting platform for hilly orchards had a high tilting stability performance and could adapt to the operating conditions of hills with slope angles from 5°to 20°.The results of the range analysis and ANOVA showed that the influence intensity of factors on tilting stability wasβ1>h>m>β2;at the same time,β1,h,and m exerted significant effect on tilting *** tilting stability first decreased and then either increased or decreased with the increasing lifting height;it gradually decreased with the increasing *** also showed that the position of the manned

关键词： orchard-lifting platform hills areas tiling stability influencing factors analysis and experiment

Effects of fan speed on spray deposition and drift for targeting air-assisted sprayer in pear orchard

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2016年第4期9卷 53-62页

作者： Qiu Wei Zhao Sanqin ding weimin Sun Chengda Lu Jiang Li Yinian Gu Jiabing College of Engineering/Key Laboratory of Intelligent Equipment for Agriculture of Jiangsu Province Nanjing Agricultural UniversityNanjing 210031China

In order to reduce the application dosage of pesticides,a targeting air-assisted(TAA)sprayer was developed and tested in this *** trees were assayed by an infrared detection system to determine if the canopy needs to be *** TAA sprayer was compared with conventional air-assisted(CAA)sprayers,and the impacts of various fan speeds(0,800 r/min,1300 r/min,and 1800 r/min)on spray deposition,coverage,and drift amount were *** 2R was used as tracer to measure spray deposition under each *** coverage and canopy deposition were best when the CAA application fan speed was increased to 1300 r/min,but at higher fan speeds,spray deposition and coverage in canopy did not increase because extra air flow blew droplets from the ground into the *** TAA spraying,droplet sizes increased at opening and closing *** spray effects were achieved when the auxiliary airflow velocity was increased at a fan speed of 1800 r/*** research provides a useful reference for the design of TAA and parameters optimization method with respect to the relationship between droplets deposition into tree canopy,ground and drift in the air.

关键词： sprayers infrared detectors spray deposition drift fruit trees plant protection

Discrete element method simulation of disc type furrow openers in paddy soil

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2020年第4期13卷 103-110页

作者： Fiaz Ahmad Baijing Qiu Qishuo ding weimin ding Zahid Mahmood Khan Muhammad Shoaib Farman Ali Chandio Abdur Rehim Abdul Khaliq School of Agricultural Equipment Engineering Jiangsu UniversityZhenjiang 212013JiangsuChina College of Engineering Nanjing Agricultural UniversityNanjing 210031China Department of Agricultural Engineering Bahauddin Zakariya University 60800MultanPakistan Department of Farm Power and Machinery Sindh Agricultural UniversityTandojam 70060Pakistan Department of Soil Science Bahauddin Zakariya University 60800MultanPakistan Department of Irrigation and Drainage University of AgricultureFaisalabad 38000Pakistan

For granular materials,discrete element modeling is one of the best computer tools to simulate their behavior and interactions.A field experiment was carried out to evaluate the performance of disc furrow openers in paddy *** element simulation was done to develop a 3D DEM model for notched,toothed and double disc furrow openers using EDEM *** Mindlin contact model with bonding was applied for simulation to fulfill the obligations of the soil moisture and bonding between the cohesive *** and field experimental data were compared to determine the applicability in the different working *** results of the simulation validated the applicability of the Hertz-Mindlin contact model with bonding to simulate the no till paddy soil using an extremely narrow tillage *** calibrated value of normal and shear stiffness was 5×10^(7)N/m,and the calibrated value of bond normal and shear strength was 3×10^(7)*** relative error(-1.7%to 20.6%)for the double disc furrow opener was lower as compared with that notch typed(29.2%to 44.4%)and toothed type(31.5%to 45.9%)furrow openers.

关键词： soil tillage discrete element method discrete element modeling furrow opener paddy soil

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

科里奥利颗粒料质量流量计流量公式理论分析

仪器仪表学报 2007年第1期28卷 136-139页

作者：丁永前丁为民南京农业大学工学院南京210031

本文通过对科里奥利固体颗粒料质量流量计的结构分析,认为该流量计无法获取实时的质量流量,并对公开的瞬时流量计算公式进行了理论分析,说明其理论上的缺陷,给出了详细的推证过程和更为精确的理论计算方法和措施。

关键词：科里奥利流量计质量流量固体颗粒

UHRF1/DNMT1—MZF1 axis-modulated intragenic site-specific CpGI methylation confers divergent expression and opposing functions of PRSS3 isoforms in lung cancer

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Acta Pharmaceutica Sinica B 2023年第5期13卷 2086-2106页

作者： Shuye Lin Hanli Xu Lin Qin Mengdi Pang Ziyu Wang Meng Gu Lishu Zhang Cong Zhao Xuefeng Hao Zhiyun Zhang weimin ding Jianke Ren Jiaqiang Huang Cancer Research Center Beijing Chest HospitalCapital Medical UniversityBeijing Tuberculosis and Thoracic Tumor InstituteBeijing 101149China College of Life Sciences&Bioengineering Beijing Jiaotong UniversityBeijing 100044China Department of Endoscopic Diagnosis and Treatment Beijing Chest HospitalCapital Medical UniversityBeijing Tuberculosis and Thoracic Tumor InstituteBeijing 101149China CAS Key Laboratory of Computational Biology Shanghai Institute of Nutrition and HealthUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai 200031China

As confusion mounts over RNA isoforms involved in phenotypic plasticity,aberrant CpG methylation-mediated disruption of alternative splicing is increasingly recognized as a driver of intratumor heterogeneity(ITH).Protease serine 3(PRSS3),possessing four splice variants(PRSS3-SVs;PRSS3-V1—V4),is an indispensable trypsin that shows paradoxical effects on cancer ***,we found that PRSS3 transcripts and their isoforms were divergently expressed in lung cancer,exhibiting opposing functions and clinical outcomes,namely,oncogenic PRSS3-V1 and PRSS3-V2 versus tumorsuppressive PRSS3-V3,by targeting different downstream *** identified an intragenic CpG island(iCpGI)in *** of iCpGI was mediated by UHRF1/DNMT1 complex interference with the binding of myeloid zinc finger 1(MZF1)to regulate PRSS3 *** garlic-derived compound diallyl trisulfide cooperated with 5-aza-2'-deoxycytidine to exert antitumor effects in lung adenocarcinoma cells through site-specific iCpGI demethylation specifically allowing MZF1 to upregulate PRSS3-V3 *** silencing of PRSS3-V3 via i CpGI methylation(iCpGIm)in BALF and tumor tissues was associated with early clinical progression in patients with lung cancer but not in those with squamous cell carcinoma or inflammatory ***,UHRF1/DNMT1—MZF1 axismodulated site-specific iCpGIm regulates divergent expression of PRSS3-SVs,conferring nongenetic functional ITH,with implications for early detection of lung cancer and targeted therapies.

关键词： Lung cancer Intratumor heterogeneity Splice variants Intragenic CpG methylation Protease serine 3 Myeloid zinc finger 1 UHRF1/DNMT1 5-Aza-CdR

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于EM算法的图像融合质量评价

农业工程学报 2007年第5期23卷 168-172页

作者：邓巍丁为民南京农业大学工学院南京210031

为提出一种量化评价经图像融合所产生的结果图像的质量评价方法,采用一种混合瑞利(Rayleigh)概率密度函数(pdfs)对图像边缘强度直方图建模,混合模型中各项的参数和权重通过EM算法迭代估算得到。在建立的混合瑞利概率密度函数模型中,最... 详细信息

为提出一种量化评价经图像融合所产生的结果图像的质量评价方法,采用一种混合瑞利(Rayleigh)概率密度函数(pdfs)对图像边缘强度直方图建模,混合模型中各项的参数和权重通过EM算法迭代估算得到。在建立的混合瑞利概率密度函数模型中,最小参数混合项对应图像的弱边缘,最大参数混合项对应图像的强边缘。因此,取最小参数项的标准方差作为噪声的标准方差估计,实现噪声盲估计;取最大参数项的标准方差作为图像模糊度的定量评价指标。通过估算混合瑞利pdfs模型中的参数变化可以评价图像质量。与其它图像质量评价方法相比,这种方法的最大优点是不需要知道图像构造等细节信息,不需要图像变换,只要有原始图像即可对其进行评价。而且对较小噪声也能较精确地估计。研究表明这个技术很强健,并对要评估的图像依赖很小。

关键词：图像融合图像质量评价混合瑞利概率密度函数(pdfs) EM算法