期刊文献+
共找到2,326篇文章
< 1 2 117 >
每页显示 20 50 100
Seismic damage zone and width-throw scaling along the strike-slip faults in the Ordovician carbonates in the Tarim Basin 被引量:13
1
作者 De-Bo Ma Guang-Hui Wu +3 位作者 Nicola Scarselli Xin-Sheng Luo Jian-Fa Han Zhi-Yong Chen 《Petroleum Science》 SCIE CAS CSCD 2019年第4期752-762,共11页
Understanding the scaling relation of damage zone width with displacement of faults is important for predicting subsurface faulting mechanisms and fluid flow processes. The understanding of this scaling relationship i... Understanding the scaling relation of damage zone width with displacement of faults is important for predicting subsurface faulting mechanisms and fluid flow processes. The understanding of this scaling relationship is influenced by the accuracy of the methods and types of data utilized to investigate faults. In this study, seismic reflection data are used to investigate the throw and damage zone width of five strike-slip faults a ecting Ordovician carbonates of the Tarim intracraton basin,NW China. The results indicate that fault slips with a throw less than 200 m had formed wide damage zones up to 3000 m in width. Also, damage zone width is found to have both a positive correlation and a power-law relation with throw of two orders of magnitude, with a ratio of these values varying in a range of 2–15. The relationship between throw and damage zone width is not a simple power-law and changes its slope from small to larger size faults. The results indicate that throw scales well with damage zone width for the studied faults, and hence these can be used to predict fault geometries in the Tarim Basin. The study of the wide carbonate damage zones presented here provides new insights into scaling of large-size faults, which involve multiple faulting stages. 展开更多
关键词 Fault damage zone Carbonate throw SCALING Evolution Tarim Basin
原文传递
throw的含义及用法举隅
2
作者 赵红梅 《川北教育学院学报》 2002年第3期68-69,共2页
关键词 英语教学 throw 含义 用法
在线阅读 下载PDF
Sediment generation and soil mound denudation in areas of high-density tree throw along a river valley in the Jura Mountains, Switzerland
3
作者 Philip GREENWOOD Jan BAUER Nikolaus J KUHN 《Journal of Mountain Science》 SCIE CSCD 2021年第2期377-391,共15页
A preliminary field-based investigation was undertaken in a small(<10 km^(2))river valley located in the mountainous Jura region of northwest Switzerland.The aims of the work were to assess sediment generation and ... A preliminary field-based investigation was undertaken in a small(<10 km^(2))river valley located in the mountainous Jura region of northwest Switzerland.The aims of the work were to assess sediment generation and annual sediment transport rates by tree throw on forested hillslopes,and to document surface hydrology characteristics on four fresh soil mounds associated with recent tree throws over a 24-day monitoring period.For the soil mounds,average sediment recovery ranged from 7.7-28.2 g(dry weight),equivalent to a suspended sediment concentration of 145.2-327.8 g L^(-1),and runoff coefficients ranged from 1.0%-4.2%.Based on a soil bulk density value of 1,044 kg m^(-3),upslope runoff generation areas were denuded by an average 0.14 mm by the end of the 24-day monitoring period,representing an erosion rate equivalent to 2.1 mm yr^(-1).A ca.50 cm high soil mound could therefore feasibly persist for around 200-250 years.For tree throw work,the dimensions of 215 individual tree throws were measured and their locations mapped in 12 separate locations along the river valley representing a cumulative area equivalent to 5.3 ha(av.density,43 per ha).Tree throws generated a total of 20.1 m^(3) of fine-sediment(<2 mm diameter),or the equivalent of 3.8×10^(-4) m^(3) m^(-2).The process of tree throw was originally attributed to two extreme weather events that occurred in west and central Europe in late December 1999.Taking the 18-year period since both storms,this represents an annual sediment transport rate of 2.7×10^(-5) m^(3) m^(-1) yr^(-1).Exploring the relationship with wind on fall direction,65.5%of tree throws(143)generally fell in a downslope direction irrespective of hillslope aspect on which they were located.This infers that individual storms may not have been responsible for the majority of tree throws,but instead,could be associated with root failure.Given the high density of tree throws and their relative maturity(average age 41 years),we hypothesise that once trees attain a certain age in this river valley,their physiognomy(i.e.height,mass and centre of gravity)compromises their ability to remain securely anchored.We tentatively attribute this possibility to the presence of bedrock close to the surface,and to the shallow soil profile overlaying steep hillslopes. 展开更多
关键词 Tree throw Hillslope processes Sediment generation mechanism Sediment transport rate Soil mound Ibach river valley
原文传递
Double Band Double-Pulley Repair for Articular Surface Partial Tears of the Supraspinatus in Throwing Athletes: Improving the Transtendon Technique
4
作者 Osvaldo Garcia Martinez Eduard Buess Diosveny Gonzales Hernandez 《Open Journal of Orthopedics》 2012年第4期150-154,共5页
Disabled shoulders of throwing athletes typically present with extended undersurface partial tears of the rotator cuff, which include the posterior supraspinatus and the anterior infraspinatus tendon to a variable ext... Disabled shoulders of throwing athletes typically present with extended undersurface partial tears of the rotator cuff, which include the posterior supraspinatus and the anterior infraspinatus tendon to a variable extent. We propose a modified transtendon repair technique to adequately treat this subset of patients. The repair includes two double-loaded anchors, at the anterior and the posterior end of the tear, respectively. With the help of an angulated penetrator we create a medial and a lateral band of sutures on top of the cuff, producing a broad contact in the tendon-to-bone interface. All the 9 so far operated patients were young men, 7 of them base-ball pitchers, and 5 active in competitive sports. The Constant Score rose from 72 points preoperatively to 99 points at 12 months follow-up. Three of the still active pitchers were able to return to their previous level in sports after one year. The improved footprint contact of our novel repair construct should allow for better healing and, therefore, a higher chance of return to competition. 展开更多
关键词 Partial Tear SUPRASPINATUS Tendon throwING Athlete PASTA-Lesion PAINT-Lesion
暂未订购
Kinematic Characteristics Analysis and Parametric Solving of Snow Melting Agent Throwing Mechanism with Variable Crank Length
5
作者 Wenwu Liu Nianli Lu Hongxin Liu 《Journal of Harbin Institute of Technology(New Series)》 CAS 2021年第4期60-66,共7页
Variable crank length cam⁃linkage mechanism has attracted much attention due to its compact overall structure when realizing complex motion laws.According to the special trajectory requirements,the kinematic character... Variable crank length cam⁃linkage mechanism has attracted much attention due to its compact overall structure when realizing complex motion laws.According to the special trajectory requirements,the kinematic characteristics and parameters of the mechanism have been analyzed and solved,which lays foundation for the implementation of the variable crank length snow melting agent throwing mechanism designed in this paper.Based on the trajectory equation of the point,the mathematical model of the throwing mechanism was established,and the theoretical trajectory of the end point of the throwing mechanism was obtained by programming.The parametric modeling and trajectory drawing were carried out by computer aided three⁃dimensional interactive application(CATIA),and the correctness of the mathematical model was verified by comparison.The regional trajectory distribution characteristics of the end points of the throwing mechanism were studied by using the trajectory region location method,and the influence of various parameters on the trajectory was investigated by using the numerical cycle comparison method.The human⁃computer interaction system of snow melting agent throwing mechanism with variable crank length was constructed by using Microsoft Visual Basic(VB)software.Based on the restriction conditions,the optimum combination of structural adjustment parameters and operational parameters suitable for Harbin first⁃class roads was obtained by using orthogonal test table,which provides an effective method to solve the parameters of the variable crank length cam mechanism with smooth impulse trajectory. 展开更多
关键词 throwing mechanism variable crank length cam mechanism mathematical model kinematic characteristics parametric solving
在线阅读 下载PDF
Appearance of Jiangzao 361, a Conventional Early Indica Rice Variety, in Throwing Demonstration Experiment and Its Matching Throwing Technique
6
作者 胡金和 张志英 +4 位作者 祝飞 曾良明 彭裕建 胡玉平 杨小华 《Agricultural Science & Technology》 CAS 2017年第12期2331-2334,共4页
In this paper, the characteristics of Jiangzao 361, as well as its appear- ance in throwing transplanting are introduced, and the high-yielding throwing tech- nique for Jiangzao 361 is summed up. On the basis of the e... In this paper, the characteristics of Jiangzao 361, as well as its appear- ance in throwing transplanting are introduced, and the high-yielding throwing tech- nique for Jiangzao 361 is summed up. On the basis of the experimental demon- stration, the corresponding matching throwing technique is put forward. 展开更多
关键词 Conventional early indica rice Jiangzao 361 throwing technology
在线阅读 下载PDF
A Bail-Out Plan Throws outfor SMEs
7
作者 Li Zhen 《China's Foreign Trade》 2008年第Z3期32-,共1页
From the beginning of 2008,together with the appreciation of the RMB and the rising costs of labor and raw materials,tight monetary policies have contributed to the fi- nancial plight of small and medium-sized enterpr... From the beginning of 2008,together with the appreciation of the RMB and the rising costs of labor and raw materials,tight monetary policies have contributed to the fi- nancial plight of small and medium-sized enterprises(SMEs),especially those heav- ily reliant on exports. 展开更多
关键词 A Bail-Out Plan throws outfor SMEs
在线阅读 下载PDF
A Corpus-based Comparative Study of the Semantic Collocations of English and Chinese THROW Verbs
8
作者 李林夕 《海外英语》 2020年第6期94-95,共2页
A verb plays an vital role in a sentence, therefore the study of this perspective attracts numerous scholars. Particularly, corpus-based study has increasing attention in recent years. The present study chooses the TH... A verb plays an vital role in a sentence, therefore the study of this perspective attracts numerous scholars. Particularly, corpus-based study has increasing attention in recent years. The present study chooses the THROW verbs in both English and Chi?nese as the subject. The author applies"collocated"function or"pattern query"in two corpus, then analyzes the distinctions of the semantic collocation of the THROW verbs. The findings show that although these verbs belong to the same categorization in a limit?ed range of the specific histories and cultures, there is no one-to-one corresponding relation of these THROW verbs in translation across the two languages. 展开更多
关键词 throw VERB SEMANTIC COLLOCATION CORPUS-BASED study
在线阅读 下载PDF
Stories of Horror Throws Light on Cruelty of Serfdom in Old Tibet
9
作者 ZHIQING 《The Journal of Human Rights》 2003年第5期39-40,共2页
We are going to tell you some stories that took place in old Tibet, before the Democratic Reform in the late 1950s. about how, for the sole "crime" of being slaves or serfs, people had their limbs amputated,... We are going to tell you some stories that took place in old Tibet, before the Democratic Reform in the late 1950s. about how, for the sole "crime" of being slaves or serfs, people had their limbs amputated, eyes gouged out or noses cut off. These stories of horror might be beyond comprehension of any person with the least sense of human civilization, even though they are real. The system of serfdom practiced in old Tibet featured a combination of civil and 展开更多
关键词 in be on Stories of Horror throws Light on Cruelty of Serfdom in Old Tibet of
原文传递
Italian Textile Industry: Throw an Embroidered Ball in the Chinese Market
10
作者 Ren Yan 《China Textile》 2009年第4期40-43,共4页
Throwing an embroidered ball is an act of seeking marriage practiced by noble family maidens in ancient China. March 2009, the early spring of Beijing saw Italian textile industry's passion for a close relationshi... Throwing an embroidered ball is an act of seeking marriage practiced by noble family maidens in ancient China. March 2009, the early spring of Beijing saw Italian textile industry's passion for a close relationship with the Chinese market after a global shiver in the freezing economic winter. It is a ball of elegance, quality and sincere cooperation, which is to become larger and more attractive with the stable development of Chinese textile industry and the ever expansion of Chinese consumption market. 展开更多
关键词 throw an Embroidered Ball in the Chinese Market Italian Textile Industry BALL
在线阅读 下载PDF
Simulation and experimental research on line throwing rocket with flight 被引量:2
11
作者 Wen-bin GU Ming LU +3 位作者 Jian-qing LIU Qin-xing DONG Zhen-xiong WANG Jiang-hai CHEN 《Defence Technology(防务技术)》 SCIE EI CAS 2014年第2期149-153,共5页
The finite segment method is used to model the line throwing rocket system.A dynamic model of line throwing rocket with flight motion based on Kane's method is presented by the kinematics description of the system... The finite segment method is used to model the line throwing rocket system.A dynamic model of line throwing rocket with flight motion based on Kane's method is presented by the kinematics description of the system and the consideration of the forces acting on the system.The experiment designed according to the parameters of the dynamic model is made.The simulation and experiment results,such as range,velocity and flight time,are compared and analyzed.The simulation results are basically agreed with the test data,which shows that the flight motion of the line throwing rocket can be predicted by the dynamic model.A theoretical model and guide for the further research on the disturbance of rope and the guidance,flight control of line throwing rocket are provided by the dynamic modeling. 展开更多
关键词 火箭系统 飞行运动 实验 仿真 动态模型 有限段方法 参数设计 飞行时间
在线阅读 下载PDF
Optimization and experimental study of the auxiliary mechanism for organic fertilizer side throwing
12
作者 Hongxin Liu Yongtao Xie +1 位作者 Yijian Zhao Jiajie Shang 《International Journal of Agricultural and Biological Engineering》 2025年第4期157-169,共13页
To correct the working state of a throwing component and achieve an ideal narrow,far,and uniform material projectile flow for a side-throwing device for organic fertilizer with inclined opposing discs,a systematic opt... To correct the working state of a throwing component and achieve an ideal narrow,far,and uniform material projectile flow for a side-throwing device for organic fertilizer with inclined opposing discs,a systematic optimization of the auxiliary mechanisms(baffle,upper deflector,and side deflector)was performed.Starting from a basic analysis of the working principles of each side-throwing device component,theoretical modeling and MATLAB numerical calculations were used to determine the departure angle providing the farthest fertilizer distance,as well as the maximum and minimum throwing angles required to achieve a target distance of 10 m.These calculations informed the optimization and configuration of the basic structures of each auxiliary mechanism component.The impact of the baffle on fertilizer movement was analyzed,leading to an optimization of the baffle’s height and its horizontal position in relation to the main throwing disc,guiding the design of the discharge port structure.Combining the theoretical analysis results,the surface of the upper deflector was fitted,and a side deflector was added to assist in limiting the scattering angle of the projectile flow.An EDEM simulation showed that the optimized auxiliary mechanisms worked well together,resulting in a narrower discharge width,a more concentrated projectile flow,and improved uniformity in spreading.Prototype testing confirmed that from the side projection angle between the spreading direction and vertically upward,the projectile flow angle domain was adjusted from 18°-45°to 23°-32°.With the optimization of other auxiliary mechanisms,the coefficient of variation in spreading uniformity decreased from 25.95%to 19.21%,the effective throwing distance increased from 10.1 to 11.2 m,and the scattering angle decreased from 12°to 4°,effectively enhancing the performance of the side-throwing device. 展开更多
关键词 organic fertilizer side throwing auxiliary mechanism optimization research virtual simulation EXPERIMENT
原文传递
青贮饲料收获机自动跟随抛送系统研究现状与发展趋势 被引量:1
13
作者 张姬 孙振洋 +3 位作者 宋占华 于镇伟 闫云鹏 田富洋 《农机化研究》 北大核心 2026年第2期284-292,共9页
青贮饲料因具有生产成本低、收获效益高、原料易得和营养均衡等优点,逐渐成为畜牧产业的主要饲料。传统青贮收获作业中人工依赖度高、抛料均匀性不足且抛送筒控制人员存在一定的安全隐患。青贮饲料收获机自动跟随抛送系统通过信息采集... 青贮饲料因具有生产成本低、收获效益高、原料易得和营养均衡等优点,逐渐成为畜牧产业的主要饲料。传统青贮收获作业中人工依赖度高、抛料均匀性不足且抛送筒控制人员存在一定的安全隐患。青贮饲料收获机自动跟随抛送系统通过信息采集设备实时获取料箱位置与环境动态信息,根据设定的青贮饲料填充模式进行抛送作业,解析填充状态,同时液压伺服控制系统根据识别定位情况动态调节抛送筒旋转角度与出料高度,实现青贮饲料落料点的控制。本文系统综述了当前国内外青贮饲料收获机自动跟随抛送系统的研究现状;分析了机器视觉、激光雷达与传感器在自动抛送系统中的工作原理与具体应用方法;针对我国青贮饲料收获机自动跟随抛送系统发展存在的问题,提出了研发多模态感知架构、开发高动态液压伺服系统与低惯量抛送筒材料、构建“青贮机-伴随车”群体协同作业模式的建议;同时,对青贮饲料收获机自动跟随抛送系统的发展方向进行预测,以期为我国青贮饲料收获机自动跟随抛送系统的研究提供参考。 展开更多
关键词 青贮饲料收获机 自动跟随抛送系统 机器视觉 激光雷达 目标检测
在线阅读 下载PDF
精准播种与定点抛栽对水稻秧苗素质与产量的影响
14
作者 王志刚 黄颂迪 +7 位作者 章文斌 陈惠哲 张玉屏 向镜 张义凯 徐逸文 王亚梁 陈叶平 《中国稻米》 北大核心 2026年第1期94-96,101,共4页
本试验以籼粳杂交稻甬优31为材料,研究了两种不同播种方式(撒播与精准播种)和两种抛秧方式(人工撒抛与定点抛栽)对水稻秧苗素质及产量的影响。结果显示,精准播种处理的秧苗在株高、叶龄、根长、茎基宽以及干质量等方面均优于撒播处理,... 本试验以籼粳杂交稻甬优31为材料,研究了两种不同播种方式(撒播与精准播种)和两种抛秧方式(人工撒抛与定点抛栽)对水稻秧苗素质及产量的影响。结果显示,精准播种处理的秧苗在株高、叶龄、根长、茎基宽以及干质量等方面均优于撒播处理,除株高和干质量外,其余各项指标的差异均达到显著或极显著水平,这表明精准播种处理的秧苗素质明显优于撒播处理;产量及其构成因子两者尽管差异不显著,但精准播种处理的总体表现优于撒播处理。对于抛秧方式方面,定点抛栽处理的穗长、每穗实粒数、千粒重和产量分别比人工撒抛处理显著高5.39%、6.11%、2.74%和5.14%。精准播种与定点抛栽相结合的处理相较撒播与人工撒抛相结合的处理,显著增产7.38%。由此可见,精准播种与有序抛栽对于培育健壮秧苗以及实现水稻高产具有重要意义。 展开更多
关键词 水稻 精准播种 定点抛栽 有序种植 产量
在线阅读 下载PDF
苏北盆地高邮凹陷深层页岩油压裂关键技术研究
15
作者 黄晓凯 黄越 +1 位作者 金智荣 何雷宇 《油气藏评价与开发》 北大核心 2026年第2期443-450,共8页
苏北盆地高邮凹陷花庄地区是江苏油田页岩油勘探的重点区块。其中,花庄Ⅱ区块页岩埋深超4000 m,其资源量占花庄地区页岩油总资源量的42%,实现该区块高效开发对江苏油田的页岩油勘探开发工作具有重大战略意义。然而,随着埋深增加,该区块... 苏北盆地高邮凹陷花庄地区是江苏油田页岩油勘探的重点区块。其中,花庄Ⅱ区块页岩埋深超4000 m,其资源量占花庄地区页岩油总资源量的42%,实现该区块高效开发对江苏油田的页岩油勘探开发工作具有重大战略意义。然而,随着埋深增加,该区块页岩油压裂面临施工压力高、加砂难度大等挑战。针对上述问题,研究团队以提高复杂度、扩大支撑面积和提升导流能力等思路为目标,开展了水力压裂物理模拟实验,分析不同排量和压裂液黏度对裂缝形态的影响规律,并采用数值模拟方法对分段分簇设计、投球暂堵工艺、支撑剂组合等进行优化。研究表明:采用中高黏度压裂液高排量注入,可提高裂缝穿层能力,但会导致开启的层理数量减少,且裂缝扩展面积相对较小;而采用低黏度压裂液和常规排量注入,更易于沟通开启层理缝。在分段分簇设计方面,单段少簇布缝有利于集中造缝能量,促进各簇裂缝均衡进液、进砂。模拟结果显示:单段设置5~6簇时,能满足裂缝均衡扩展和裂缝支撑效果,同时开展不同送球排量、暂堵球数量和直径下暂堵球对炮眼暂堵影响模拟研究,并对投球暂堵工艺参数进行优化,送球排量在12~14 m^(3)/min之间、暂堵球直径为15 mm、暂堵球数量为孔眼数的50%~60%。结合复杂裂缝支撑剂运移铺置模拟,通过模拟确定最佳支撑剂组合及泵注参数,提高改造效果。该工艺在HY7井成功实施,峰值日产油量达到52.3 t,单井最终可采储量为4.6×10^(4)t,为江苏油田花庄Ⅱ区块深层页岩勘探带来重大突破,对同类型页岩油开发具有重要的借鉴意义。 展开更多
关键词 苏北盆地 深层页岩油 密切割布缝 投球暂堵 组合粒径
在线阅读 下载PDF
基于神经网络和抛物特征的改进MOG-SORT高空抛物检测算法
16
作者 陈卫东 刘萌 武文龙 《燕山大学学报》 北大核心 2026年第1期68-75,共8页
随着高楼的不断增多,高空抛物事件日益增加,给个人安全和公共安全都带来了挑战。高空抛物检测过程中存在背景复杂、抛物目标小、抛物外观特征不明显、抛物跟踪易丢失等问题。本文使用神经网络对混合高斯背景建模算法进行扩展,并根据抛... 随着高楼的不断增多,高空抛物事件日益增加,给个人安全和公共安全都带来了挑战。高空抛物检测过程中存在背景复杂、抛物目标小、抛物外观特征不明显、抛物跟踪易丢失等问题。本文使用神经网络对混合高斯背景建模算法进行扩展,并根据抛物特征改进简单在线实时跟踪(SORT)算法解决上述高空抛物问题。首先,为解决小目标抛物及复杂背景问题,引入区域条件滤波减少前景检测中的非抛物前景;其次,为解决抛物外观特征不明显的问题,使用多帧融合技术增强运动特征并设计轻量级分类网络来区分抛物物体:最后,为解决抛物跟踪易丢失的问题,根据抛物特征改进了SORT的状态空间和匹配度量。实验结果表明:改进后的混合高斯背景建模算法,在召回率下降6.50%的情况下,检测数量减少97.14%;改进后的SORT算法,ID切换数量减少51.61%,MOTA指标提升8.74%,TIOU指标提升8.02%. 展开更多
关键词 高空抛物检测 运动小目标检测 混合高斯背景建模 SORT
在线阅读 下载PDF
第16届全运会田径投掷项目各主要省市竞技实力前瞻
17
作者 曹司雨 李婷 《四川体育科学》 2026年第1期74-80,136,共8页
为揭示全运会投掷项目竞技格局演变规律,以第13—15届全运会投掷项目竞赛数据为研究对象,采用静态与动态分析、区域对比、模型构建与预测等方法,系统探究省市竞技实力演变、区域差异及整体发展趋势,并构建“奖牌指标+成绩指标+潜力指标... 为揭示全运会投掷项目竞技格局演变规律,以第13—15届全运会投掷项目竞赛数据为研究对象,采用静态与动态分析、区域对比、模型构建与预测等方法,系统探究省市竞技实力演变、区域差异及整体发展趋势,并构建“奖牌指标+成绩指标+潜力指标”三维评价体系,基于灰色预测模型对第16届全运会进行展望。研究表明:近三届投掷项目省市格局呈现“传统强省稳中有调、新兴省市精准突破”特征,江苏、山东、河北稳居第一梯队,河南、湖北等通过专项深耕跻身第二梯队;区域竞技实力呈“东强西弱、北强南弱”格局,华东区域为核心竞争力区,区域差距持续扩大且两极分化显著;项目整体竞技水平稳步上升,男子铁饼、女子铅球等项目进步突出,训练科学化与政策支持为核心驱动力。构建的评价体系契合实际赛事格局,预测第16届全运会将延续“强省垄断、专项深耕”特征,江苏有望蝉联领跑,新兴省市将进一步冲击奖牌格局。 展开更多
关键词 全运会 投掷项目 竞技实力 评价体系 灰色预测
在线阅读 下载PDF
不同抛秧立苗状态对甬优1540生长与产量的影响
18
作者 李慧 兰天明 +4 位作者 王晶卿 唐承翰 张玉屏 王志刚 王亚梁 《杂交水稻》 北大核心 2026年第1期71-75,共5页
以籼粳交三系杂交水稻甬优1540为材料,设置J1(平躺苗,秧苗与水平面夹角约0°)、J2(倾斜苗,秧苗与水平面夹角约45°)和J3(直立苗,秧苗与水平面夹角约90°)3种抛秧立苗状态处理,考察其对秧苗存活率、茎蘖动态、成穗率、干物... 以籼粳交三系杂交水稻甬优1540为材料,设置J1(平躺苗,秧苗与水平面夹角约0°)、J2(倾斜苗,秧苗与水平面夹角约45°)和J3(直立苗,秧苗与水平面夹角约90°)3种抛秧立苗状态处理,考察其对秧苗存活率、茎蘖动态、成穗率、干物质积累量、产量及其构成因素的影响。结果表明,各处理的秧苗成活率、茎蘖数、高峰苗数、各生育期单丛和群体干物质积累量、产量、有效穗数、每穗总粒数、结实率均表现为J3>J2>J1,且J3处理的秧苗成活率、各生育期单丛和群体干物质积累量、产量、有效穗数、每穗总粒数和结实率均显著高于J1处理,J2处理的秧苗成活率、抽穗期和成熟期群体干物质积累量、产量、有效穗数、每穗总粒数、结实率均显著高于J1处理,各处理的成穗率差异不显著。综上,直立苗提高了秧苗成活率,增加了茎蘖数、高峰苗数和干物质积累量,进而显著增加有效穗数和每穗总粒数,显著提高结实率,产量显著提高。 展开更多
关键词 抛秧 立苗状态 水稻产量 甬优1540
原文传递
烟苗移栽机自动取投苗机械手运动学分析与优化
19
作者 尚志伟 梁永欣 +6 位作者 陈俊鸿 张涛 何彦龙 石乔 何坤奇 张昊越 刘剑雄 《农机化研究》 北大核心 2026年第4期148-154,共7页
针对烟苗机械化移栽过程中快速自动取投苗导致的振动冲击和基质散坨问题,构建了一款烟苗移栽机自动取投苗机械手虚拟模型,建立了机械手的运动学模型和分析坐标体系,得到了所述坐标体系间变换映射的方法,研究和优化了主要构件的运动规律... 针对烟苗机械化移栽过程中快速自动取投苗导致的振动冲击和基质散坨问题,构建了一款烟苗移栽机自动取投苗机械手虚拟模型,建立了机械手的运动学模型和分析坐标体系,得到了所述坐标体系间变换映射的方法,研究和优化了主要构件的运动规律。结果表明:当太阳轮、星轮Ⅱ中心距与连杆长度相等时,指尖往返轨迹完全重合;连杆轴的运动轨迹为一空间椭圆,其长半轴为太阳轮、星轮Ⅱ中心距与连杆长度之和,短半轴为两者之差的绝对值;当滑辊轨迹约束槽中心线C_(4)C_(5)段的斜率与连接轴椭圆轨迹长半轴的斜率相等时,则取投苗姿态保持不变;当取苗指的运动姿态与指尖运动轨迹的切线方向保持一致时,插入基质取苗指的迎土面积和迎土面积变化率最小;滑辊轨迹约束槽的五段中心线需组合优化,以增强机械手的整体运行平稳性。研究结果为提高自动取投苗速度、降低苗和基质块的损伤提供了理论依据。 展开更多
关键词 烟苗 移栽 自动取投苗 机械手 运动优化
在线阅读 下载PDF
链钵自动移栽机挡板输送带取投苗及断链装置设计与试验
20
作者 张淯钦 黄小毛 +4 位作者 何义川 祝菊红 黄亚东 李宸位 邹金宜 《农业工程学报》 北大核心 2026年第1期13-24,共12页
针对常规链式纸钵育苗移栽技术株距固定导致的作业模式单一、应用场景受限,无法满足大株距作物移栽需求等问题,该研究提出一种基于挡板输送带取投苗及断链装置的链钵自动移栽装置,通过挡板输送带取投苗装置、断链装置与栽植装置协调动作... 针对常规链式纸钵育苗移栽技术株距固定导致的作业模式单一、应用场景受限,无法满足大株距作物移栽需求等问题,该研究提出一种基于挡板输送带取投苗及断链装置的链钵自动移栽装置,通过挡板输送带取投苗装置、断链装置与栽植装置协调动作,实现链钵苗移栽过程中取苗、运苗、断链、投苗、栽植等关键工序的自动化作业。结合链钵苗移栽作业特点与农艺要求,对挡板输送式取投苗同步带、断链装置、传动系统和投苗姿态矫正装置等关键部件进行分析,确定了相关结构参数。以适栽期番茄链钵苗为对象,进行了单因素台架试验,并开展了苗龄、同步带倾斜角、移栽频率对断链成功率和投苗成功率影响的三因素三水平正交试验。结果表明:苗龄29 d,同步带倾斜角4°和移栽频率55株/min时移栽效果较优,台架试验的断链成功率为92.44%,投苗成功率94.60%;田间试验的断链成功率为90.62%,投苗成功率为93.10%,满足链钵苗移栽机作业性能要求。研究结果可为自动化移栽装置的研发提供参考。 展开更多
关键词 移栽 自动移栽机 链式纸钵 取投苗装置 断链装置
在线阅读 下载PDF
上一页 1 2 117 下一页 到第
使用帮助 返回顶部