检索结果-南通市图书馆

Design and test of the key components for a combing-type tobacco harvester

International Journal of Agricultural and Biological Engineering 2024年第1期17卷 145-153页

作者： Chaoran Sun Shaohui Tan Songling Sun Mingtao Xiao Limei Chen Wenke Ai Zhihua Qiu Ping Jiang Yang He School of Mechanical and Electrical Engineering Hunan Agricultural UniversityChangsha 410128China Truking Technology limited Ningxiang 410600HunanChina Construction of tobacco leaf production infrastructure of Hunan Province Company of china National Tobacco corporation office Changsha 410009China

In response to the problems of low efficiency,high labor intensity,and low mechanization in manual tobacco harvesting,a comb-off tobacco picking device for southern hilly tobacco areas was designed following the agronomic requirements and the principle of manual picking of tobacco harvesting in southern *** device was composed of the power chassis,picking mechanism,and storage *** study involved the theoretical analysis,structural design,and modeling of the key components,such as chassis structure,combing-type picking mechanism,and power synchronization *** results of the motion analysis and calculation of the picking process demonstrated that the adjustment range of the comb chain elevation angles was from 12.4°to 20.9°,the comb rod installation distance was 76.2 mm,and the synchronizing mechanism transmission ratio was 3:***-factor test and three-factor three-level orthogonal test was performed with the forward speed of the chassis,the distance between the picking device baffles and the elevation angle of the chain with the combing bar as test factors,and the rate of broken and missed tobacco picking as evaluation *** was revealed that the optimal combination of the forward speed of the chassis,the distance between the baffles,and the chain elevation angle were 1.5 km/h,75 mm,and 12.4°,***,verification tests suggested that the breakage rate of tobacco leaves was 9.99%,and the probability of missed tobacco picking was 7.31%,both of which satisfy the agriculture requirements and the operational requirements in the agricultural machinery certification syllabus.

关键词： harvesting machinery leaf tobacco combing-type tiered harvest synchronizing mechanism

来源：

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

A Loss-model-based Efficiency Optimization Control Method for Induction Traction System of High-speed Train under Emergency Self-propelled Mode

引用

CES Transactions on Electrical Machines and Systems 2024年第2期8卷 227-239页

作者： Yutong Zhu Yaohua Li Institute of Electrical Engineering Chinese Academy of Sciences Beijing 100190China University of Chinese Academy of Sciences Beijing 100190China china Academy of Railway Sciences corporation limited(Beijing Zongheng Electromechanical Technology Co.Ltd Beijing 100081 China IEEE

Increasing attention has been paid to the efficiency improvement of the induction traction system of high-speed trains due to the high demand for energy saving. In emergency self-propelled mode, however, the dc-link voltage and the traction power of the motor are significantly reduced, resulting in decreased traction efficiency due to the low load and low speed operations. Aiming to tackle this problem, a novel efficiency improved control method is introduced to the emergency mode of high-speed train traction system in this paper. In the proposed method, a total loss model of induction motor considering the behaviors of both iron and copper loss is established. An improved iterative algorithm with decreased computational burden is then introduced, resulting in a fast solving of the optimal flux reference for loss minimization at each control period. In addition, considering the parameter variation problem due to the low load and low speed operations, a parameter estimation method is integrated to improve the controller's robustness. The effectiveness of the proposed method on efficiency improvement at low voltage and low load conditions is demonstrated by simulated and experimental results.

关键词： Efficiency optimization Induction motor Loss model control Motor drives Traction system

来源：

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

Energy partition in laser-induced cavitation bubbles near the rigid wall with a gas-containing hole

引用

Journal of Hydrodynamics 2024年第3期36卷 435-443页

作者： Dong-qiao He Hai-gang Wen Si-yuan Geng Chen-xi Yang Qiang Zhong Zhi-feng Yao College of Water Resources and Civil Engineering China Agricultural UniversityBeijing100083China Powerchina Beijing Engineering corporation limited Beijing100024China State Key Laboratory of Efficient Utilization of Agricultural Water Resources Beijing100083China Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System China Agricultural UniversityBeijing100083China

To investigate the energy partition in laser-induced cavitation bubbles near the rigid wall with a gas-containing hole,we utilized a nanosecond resolution photography system based on a Q-switched Nd:YAG laser and conventional industrial camera to carefully observe the transient process of bubble collapse near the rigid wall with a gas-containing *** analyzed the generation of collapse microjets and the emission of collapse shock *** found that the cavitation bubble near the rigid wall with a gas-containing hole collapsed at different times and space,and produced various types of shock *** on the far field pressure information of the shock waves measured by hydrophone,the energy of the shock waves generated by the bubble collapse near the rigid wall with a gas-containing hole is calculated for the first *** results show that the ratio of collapse shock wave energy to bubble energy is approximately between 0.7 and 0.8.

关键词： Energy partition bubble collapse laser-induced shock wave gas-containing hole

来源：

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

Predicting torsional capacity of reinforced concrete members by data-driven machine learning models

引用

Frontiers of Structural and Civil Engineering 2024年第3期18卷 444-460页

作者： Shenggang CHEN Congcong CHEN Shengyuan LI Junying GUO Quanquan GUO Chaolai LI School of Mechanics and Civil Engineering China University of Mining and TechnologyXuzhou 211116China Jiangsu Key Laboratory Environmental Impact and Structural Safety in Engineering China University of Mining and TechnologyXuzhou 211116China china Nuclear Power Design Co.Ltd. Shenzhen 518031China School of transportation and science engineering Beihang UniversityBeijing 100191China china Construction First Group corporation limited Beijing 100161China

Due to the complicated three-dimensional behaviors and testing limitations of reinforced concrete(RC)members in torsion,torsional mechanism exploration and torsional performance prediction have always been *** the present paper,several machine learning models were applied to predict the torsional capacity of RC *** results of a total of 287 torsional specimens were collected through an overall literature *** of extreme gradient boosting machine(XGBM),random forest regression,back propagation artificial neural network and support vector machine,were trained and tested by 10-fold cross-validation *** performances of proposed machine learning models were evaluated and compared,both with each other and with the calculated results of existing design codes,i.e.,GB 50010,ACI 318-19,and Eurocode *** results demonstrated that better predictive performance was achieved by machine learning models,whereas GB 50010 slightly overestimated the torsional capacity,and ACI 318-19 and Eurocode 2 underestimated it,especially in the case of ACI *** XGBM model gave the most favorable predictions with R^(2)=0.999,RMSE=1.386,MAE=0.86,andλ=***,strength of concrete was the most sensitive input parameters affecting the reliability of the predictive model,followed by transverse-to-longitudinal reinforcement ratio and total reinforcement ratio.

关键词： RC members torsional capacity machine learning models design codes

来源：

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

Analysis on the development of chemically-improved soil in railway engineering

引用

Railway Sciences 2024年第2期3卷 216-226页

作者： Feng Chen Zhongjin Wang Dong Zhang Shuai Zeng china Academy of Railway Sciences corporation limited BeijingChina

Purpose-Explore the development trend of chemically-improved soil in railway ***/methodology/approach–In this paper,the technical standards home and abroad were *** test,field test and monitoring were carried ***–The performance design system of the chemically-improved soil should be ***/value–On the basis of the performance design,the test methods and standards for various properties of chemically-improved soil should be established to evaluate the improvement effect and control the engineering quality.

关键词： Durability Deformation Engineering properties Chemically-improved soil Performance design Test method

来源：

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

A novel nano-grade organosilicon polymer:Improving airtightness of compressed air energy storage in hard rock formations

引用

International Journal of Mining Science and Technology 2024年第3期34卷 305-321页

作者： Zhuyan Zheng Guibin Wang Chunhe Yang Hongling Ma Liming Yin Youqiang Liao Kai Zhao Zhen Zeng Hang Li Yue Han Institute of Rock and Soil Mechanics Chinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Geomechanics and Geotechnical Engineering Wuhan 430071China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400044China Powerchina Huadong Engineering corporation limited Hangzhou 310014China

Enhancing cavern sealing is crucial for improving the efficiency of compressed air energy storage(CAES)in hard rock *** study introduced a novel approach using a nano-grade organosilicon polymer(NOSP)as a sealant,coupled with an air seepage evaluation model that incorporates Knudsen ***,the initial coating application methods were outlined,and the advantages of using NOSP compared to other sealing materials,particularly regarding cost and construction techniques,were also examined and *** results indicated a significant reduction in permeability of rock specimens coated with a 7–10μm thick NOSP ***,under a 0.5 MPa pulse pressure,the permeability decreased to less than 1 n D,and under a 4 MPa pulse pressure,it ranged between4.5×10^(-6)–5.5×10^(-6)m D,marking a 75%–80%decrease in granite *** sealing efficacy of NOSP surpasses concrete and is comparable to rubber *** optimal viscosity for application lies between 95 and 105 KU,and the coating thickness should ideally range from 7 to 10μm,applied to substrates with less than 3%*** study provides new insights into air transport and sealing mechanisms at the pore level,proposing NOSP as a cost-effective and simplified solution for CAES applications.

关键词： Compressed air energy storage Lining Permeability Transient pulse method Hard rock cavern Nano-grade organosilicon polymer coating

来源：

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

A novel Ce_(0.485)Zr_(0.485)Y_(0.03)O_(2) composite oxide with surface doping of Y and its application in Pd-only three-way catalyst

引用

Rare Metals 2024年第2期43卷 749-757页

作者： Zheng Zhao Wei-Xin Zhao Yong-Qi Zhang Mei-Sheng Cui Yong-Ke Hou Dong-Ming Chen Juan-Yu Yang Zong-Yu Feng Xiao-Wei Huang National Engineering Research Center for Rare Earth Grirem Advanced Materials Co.Ltd.GRINM Group Corporation LimitedBeijing100088China Griem Hi-Tech Co.Ltd. Langfang065000China Rare Earth Functional Materials(Xiong’an)Innovation Venter Co.Ltd. Baoding071700China

The ceria-zirconia compound oxide-supported noble metal Pd(Pd@CZ)is widely used in three-way ***,the surface structure of CZ plays an important role in catalytic activity of ***,how to regulate the surface structure of CZ and clarify the structure–activity relationship is still a *** this paper,a strategy is proposed to develop high activity Pd@CZ nanocatalysts by tuning Y doping sites in *** precipitate-deposition method is developed to prepare the novel Ce_(0.485)Zr_(0.485)Y_(0.03)O_(2) composite with surface doping of Y(CZ-Y-S).In addition,the Pd@CZ-Y-S(Pd supported on CZ-Y-S)exhibits superior catalytic activity for HC,CO,and NO oxide,wherein,for CO and C_(3)H_(6) oxidation,the low-temperature activity of Pd@CZ-Y-S is still 20%higher than that of Pd@CZ-Y-B(Y bulk doping)and commercial Pd@CZ after 1000℃/4 h *** effect mechanism is further studied by density functional theory(DFT)*** with Pd@CZ-Y-B,Pd@CZ-Y-S shows the lower CO oxide reaction energy barriers due to the weaker adsorption strength of *** Y surface doping strategy could provide valuable insights for the development of highly efficient Pd@CZ catalyst with extensive applications.

关键词： Rare earth Ceria-zirconia-supported Pd Surface doping Experiment and theory Catalytic application

来源：

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

Evolution of Cenozoic sedimentary architecture in Central and Southern South china Sea basins

引用

Journal of Palaeogeography 2024年第1期13卷 35-53页

作者： Wu Tang Xiao-Jun Xie Yi-Bo Wang Lian-Qiao Xiong Jia Guo Xin Li china National Offshore Oil corporation Research Institute Beijing 100028China

The Central and Southern South china Sea(CSSCS) has a complex tectonic dynamic background and abundant oil and gas resources, which has always been a hot topic of academic and industrial ***, systematic analyses are still lacking regarding its sediment filling structure and evolution, mostly due to limited borehole penetration and poor quality of seismic reflection data for deeply buried sequences. No consensus has been reached yet on the sedimentary infilling processes, which impeded the reconstruction of the palaeogeography of Southeast Asia and the oil-and-gas exploration undertakings. Here, we illustrate the Cenozoic sedimentary evolution of the CSSCS region by synthesizing relevant data from previous literature and our own observations and displaying the evolution of depositional systems in sequential reconstructions. Besides, the controlling factors of preferred sedimentary scenarios in the CSSCS incorporate the latest interpretations of the spreading of South china Sea(SCS) as well as the demise of the hypothetical Proto-South china Sea(PSCS). The results show that there are three types of sedimentary basins in the CSSCS(foreland,strike-slip, and rift basins) with different sedimentary filling structures. The foreland basins formed a depositional pattern of ‘transition from deep water to shallow water environments', dominated by deep-water depositional systems which were formed before the Early Oligocene with submarine fans developed. Later,the foreland basins were gradually dominated by shallow-water depositional systems with deltas and shallow marine facies. The strike-slip basins showed the depositional architecture of ‘transition from lake to marine environments', i.e. the basins were dominated by lacustrine deposits during the Eocene and evolved into the marine depositional environment since Oligocene with delta developed in the western part of the basin. The depositional evolution of rift basins illustrated the characteristics of 'transiti

关键词： Central and Southern South china Sea Sedimentary filling Main controlling factors Proto-South china Sea South china Sea

来源：

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

A novel tunnel waterproof-drainage system based on double-bonded waterproofing materials and its seepage characteristics

引用

Frontiers of Structural and Civil Engineering 2024年第9期18卷 1321-1336页

作者： Xiaohe SUN Chenghua SHI Guoqing XIAO Yangyang GE Chengyong CAO School of Civil Engineering Central South UniversityChangsha 410075China Powerchina ZhongNan Engineering corporation limited Changsha 410014China State Key Laboratory of Special Functional Waterproof Materials Beijing Oriental Yuhong Waterproof Technology Co.Ltd.Beijing 101111China College of Civil and Transportation Engineering Shenzhen UniversityShenzhen 518060China

Double-bonded spray membrane waterproofing materials have excellent waterproofing performance and can improve the load-bearing capacity of tunnel linings,leading to an increasing global ***,due to the double-bonded capability of spray membrane materials,traditional interlayer drainage methods cannot be *** limitation makes it difficult to use them in drainage-type tunnels,significantly restricting their range of *** this regard,a novel tunnel waterproof-drainage system based on double-bonded spray membrane materials was proposed in this *** proposed drainage system primarily comprises upper drainage sheets and bottom drainage blind pipes,both located in the tunnel circumferential direction,as well as longitudinal drainage pipes within the ***,numerical calculation methods are employed to analyze the seepage characteristics of this system,revealing the water pressure distribution around the *** results indicate that in the novel waterproof-drainage system,the water pressure in the secondary lining exhibits a“mushroom-shaped”distribution in the circumferential direction,while the water pressure in the longitudinal direction exhibits a“wave-like”***,comparative results with other waterproof-drainage systems indicate that under typical working conditions with a water head of 160 m and a rock permeability coefficient of 10^(−6)m/s,the maximum water pressure in the secondary lining of the novel waterproof-drainage system is 0.6 *** represents a significant reduction compared to fully encapsulated waterproofing and traditional drainage systems,which respectively reduce the water pressure by 65%and 30%.The applicability analysis of the double-bonded waterproofing and drainage system reveals that it can reduce at least 40%of the static water pressure in any groundwater *** novel drainage system provides a valuable reference for the application of double-bonded spray membr

关键词： tunnel drainage spray-applied waterproofing membrane numerical simulation water pressure

来源：

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

Large-scale toppling slope under water level fluctuation of reservoir:A case of Yunnan Province,china

引用

Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3034-3046页

作者： Leilei Jin Yufeng Wei Fei Ye Wenxi Fu Jianfeng Liu Shuwu Li State Key Laboratory of Hydraulic and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China Northwest Engineering corporation limited Xi’an710065China

Landslides induced by reservoir inundation are common in Southwest china,negatively influencing hydropower *** hydropower station dam was constructed in the upper reaches of the Lancang River,accordingly causing the water level at the Lajinshengu slope to increase by 30 m.A tension crack with a visible depth of 8 m was observed in the upper sector of the Lajinshengu slope after reservoir impoundment for 170 *** the following days,numerous cracks appeared on the surface of the slope,and the maximum displacement of the slope reached 3.22 ***,a large-scale active deformation body within the Lajinshengu slope formed with an area of 2.62×10^(5)m^(2)and a volume of 1.65×10^(7)m^(3).Detailed field investigations,on-site monitoring,and centrifugal model tests were carried out to analyze the surface features,deformation characteristics,and failure mechanism of the Lajinshengu *** results show that the slope is an ancient landslide,divided into two parts(*** A and zone B)by the *** B is a traction landslide caused by the displacement of zone *** longterm inundation weakens the soft rock at the slope foot,intensifying the toppling of bedrock and consequently triggering the sliding of the overburden in zone *** failure mode of the Lajinshengu slope is a typical case of toppling-sliding failure,and the underlying rock toppling drives the overlying *** addition,early identification methods for toppling deformation covered by overburdened soil were proposed based on monitoring data and deformation signs.

关键词： Lajinshengu slope Reservoir impoundment Early identification Failure mechanism Toppling-sliding slope failure mode

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：