期刊文献+
共找到2,241篇文章
< 1 2 113 >
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:8
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
下载PDF
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
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
下载PDF
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
下载PDF
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
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
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
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
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
下载PDF
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
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
下载PDF
Operation analysis and parameter optimization of the conveying device for uniform crushed straw throwing and seed-sowing machines
12
作者 Fengwei Gu Youqun Zhao +4 位作者 Zhichao Hu Lili Shi Feng Wu Hongbo Xu Xuemei Gao 《International Journal of Agricultural and Biological Engineering》 SCIE 2023年第6期28-36,共9页
Uniform crushed straw throwing and seed-sowing machines can achieve the processes of straw chopping,straw transport,sowing,fertilization,and straw mulching at the same time,which is widely used in many areas of China.... Uniform crushed straw throwing and seed-sowing machines can achieve the processes of straw chopping,straw transport,sowing,fertilization,and straw mulching at the same time,which is widely used in many areas of China.Conveying device is one of the important components used to convey,elevate and throw straw.However,the problems of high power consumption and congestion affect the promotion of the machine.Therefore,the conveying device of uniform crushed straw throwing and seed-sowing machine was analyzed in order to determine its device operation mechanism.Kinematic and dynamic analyses of particles of crushed rice straw during lifting and dispersion are used to develop a flexible-body model of rod-shaped and agglomerate-shaped crushed straw and a coupling model including the mechanical structure of the device.By integrating computational fluid dynamics and the discrete element method,the gas-solid coupling theory in numerical simulations and motion analysis of crushed straw particles is used to determine how the flow field and motion characteristics affect the conveying performance.Besides,regression equations to describe the relationships between the factors and each assessment index were established by using the regression analysis and response surface analysis with the software Design-Expert.The effect of throwing blade speed X_(1),conveying volume of crushed straw X_(2),and pipeline diameter X_(3) on the throwing speed of crushed straw Y_(1) and specific power consumption Y2 were investigated.The highest throwing speed of crushed straw and lowest specific power consumption are the optimization goal.The results of optimization showed that the predict the best optimal parameters were 2000 r/min throwing blade rotational speed,1.4 kg/s conveying volume,and 220 mm pipeline diameter,the planter achieved a throwing speed of 12.2 m/s and specific power consumption of 9179 m^(2)/s^(2).And then a field test verification was conducted.The planter achieved a throwing speed 12.4 m/s and specific power consumption 9070 m^(2)/s^(2) while selecting the best optimal parameters.Thus,the optimal parameters can provide a high-performance operation and satisfy the actual operation requirements The results provide a theoretical basis and data support for seeding technology innovation and equipment optimization to ensure uniform crushed straw throwing in dense rice stubble fields. 展开更多
关键词 rice straw stubble uniform crushed straw throwing coupled CFD-DEM response surface analysis
原文传递
轻简化栽培稻田杂草发生趋势与防控技术 被引量:1
13
作者 马国兰 张帅 刘都才 《现代农药》 CAS 2024年第3期8-12,61,共6页
随着水稻轻简化栽培技术的应用与推广,东北稻区、西北稻区、长江流域稻区和华南稻区等水稻主产区的杂草种群演替加快,稗草、千金子和马唐等恶性杂草频繁发生,杂草抗药性水平上升迅速。若杂草防控不及时、不彻底,极易对水稻生产构成严重... 随着水稻轻简化栽培技术的应用与推广,东北稻区、西北稻区、长江流域稻区和华南稻区等水稻主产区的杂草种群演替加快,稗草、千金子和马唐等恶性杂草频繁发生,杂草抗药性水平上升迅速。若杂草防控不及时、不彻底,极易对水稻生产构成严重威胁。为此,对水稻直播、机插和抛秧等轻简化栽培稻田杂草的草相特征、发展趋势和防除方法等进行了概述,以期为制定合理、高效的轻简化栽培稻田杂草综合防控技术、水稻用农药减量增效除草方案,延缓杂草抗药性产生与发展提供借鉴。 展开更多
关键词 水稻轻简化栽培 直播 机插 抛秧 杂草 防控
下载PDF
论高空抛物侵权场合公安机关违反调查职责的赔偿责任 被引量:1
14
作者 朱晓峰 《现代法学》 CSSCI 北大核心 2024年第4期85-100,共16页
《民法典》第1254条第3款规定了高空抛物侵权场合中“依法及时调查”属于公安机关的法定职责,违反该职责所引发的法律后果在《民法典》未作规定的情况下应回到一般法,即在《人民警察法》中予以确定。其中,相应的损害赔偿责任可经由《人... 《民法典》第1254条第3款规定了高空抛物侵权场合中“依法及时调查”属于公安机关的法定职责,违反该职责所引发的法律后果在《民法典》未作规定的情况下应回到一般法,即在《人民警察法》中予以确定。其中,相应的损害赔偿责任可经由《人民警察法》第50条引致到《国家赔偿法》中进行认定。当公安机关违反调查职责导致真正侵权人难以确定时,受害人、可能加害的建筑物使用人遭受的纯粹经济损失可以纳入《国家赔偿法》的调整范围。当符合《国家赔偿法》第2条规定的构成要件时,受害人、可能加害的建筑物使用人可以向违反调查职责的公安机关主张国家赔偿。受违反安全保障义务的建筑物管理人应承担补充责任的影响,可能加害的建筑物使用人主张的赔偿责任数额与其承担的补偿责任范围相同,受害人主张的赔偿责任数额是其从真正侵权人处获得的赔偿总额与建筑物管理人承担的补充责任数额及可能加害的建筑物使用人承担的补偿责任数额相加之后的差额。 展开更多
关键词 高空抛物 公安机关 调查职责 国家赔偿 补偿责任
下载PDF
库车坳陷大北地区巴什基奇克组隐性断层特征与发育模式
15
作者 金江宁 易泽军 +5 位作者 李青 王海学 屈元基 姜涵博 李志豪 何韫多 《地质科学》 CAS CSCD 北大核心 2024年第3期760-767,共8页
库车坳陷作为塔里木盆地新生代再生前陆盆地,盐下叠瓦状构造楔发育,多个断片在巴什基奇克组发现了天然气藏。随着气藏的不断开发,多个气藏发生不同程度水侵,前人研究表明,隐性断层作为沟通底水或边水的高渗透通道,是导致水侵的主要原因... 库车坳陷作为塔里木盆地新生代再生前陆盆地,盐下叠瓦状构造楔发育,多个断片在巴什基奇克组发现了天然气藏。随着气藏的不断开发,多个气藏发生不同程度水侵,前人研究表明,隐性断层作为沟通底水或边水的高渗透通道,是导致水侵的主要原因,能否有效识别隐性断层直接影响气藏开发效果。然而,由于膏盐岩层的影响,盐下构造的地震分辨率较低,使用地震属性方法识别隐性断层难度较大。本次以大北地区为例,采用地质与地球物理相结合的思路,在钻井与地震属性方法识别的3条隐性断层基础上,通过断距—距离曲线分析主干逆冲断裂的分段性,并结合应力分析,建立了两种隐性断层发育模式。结果表明隐性断层的形成受局部应力场和区域应力场的共同控制。主干逆冲断层构造转换带是隐性断层优势发育位置,随着断层发生分段生长连接,构造转换带将由挤压应力状态逐渐变为走滑应力状态,形成的隐性断层走向也将发生变化。区域应力的走滑分量则是控制北东向隐性断层远离主干边界断层后走向,维持稳定的另一重要因素。本次研究成果将为库车坳陷隐性断层的识别和预测提供重要的地质约束。 展开更多
关键词 库车坳陷 逆冲断裂 隐性断层 断距—距离曲线 发育模式
下载PDF
不同勘探方法对浅层小断距隐伏断裂探测效果
16
作者 曾金艳 李自红 +2 位作者 陈文 扈桂让 闫小兵 《大地测量与地球动力学》 CSCD 北大核心 2024年第3期310-315,共6页
采用浅层地震勘探、钻孔联合剖面勘探、槽探3种方法联合探测临汾盆地郭家庄断裂的空间位置,并研究其活动特征。结果表明,不同探测方法对断层信息的揭示存在很大差异,浅层地震勘探在探测具有一定断距的断层,同时地层存在一定物性差异的... 采用浅层地震勘探、钻孔联合剖面勘探、槽探3种方法联合探测临汾盆地郭家庄断裂的空间位置,并研究其活动特征。结果表明,不同探测方法对断层信息的揭示存在很大差异,浅层地震勘探在探测具有一定断距的断层,同时地层存在一定物性差异的情况下能取得理想的效果,且不同的工作参数探测效果不相同;钻孔联合剖面勘探能提高对小断距断层的分辨率,但受地形及地层主观认别等因素的影响,可能会遗漏断距小、标识层薄的断层;槽探能较好地识别地表断层的微小断距,但受施工深度和施工条件影响。3种方法相结合,可以精确确定断裂的空间位置和活动特征。 展开更多
关键词 小断距 浅层地震勘探 钻孔联合剖面勘探 槽探
下载PDF
超宽窄行蕉园起垄机抛土机构设计与试验
17
作者 高锐涛 高宇 +2 位作者 孙志全 曹璨 李君 《包装工程》 CAS 北大核心 2024年第2期273-285,共13页
目的在查阅大量国内外有关起垄机构的研究文献基础上,结合新型蕉园种植模式和农艺要求,设计一种蕉园起垄机抛土机构,实现蕉园起垄机械化作业。方法对抛土起垄机构主要部件进行建模仿真,应用EDEM对抛土起垄过程进行仿真,以导向罩角度、... 目的在查阅大量国内外有关起垄机构的研究文献基础上,结合新型蕉园种植模式和农艺要求,设计一种蕉园起垄机抛土机构,实现蕉园起垄机械化作业。方法对抛土起垄机构主要部件进行建模仿真,应用EDEM对抛土起垄过程进行仿真,以导向罩角度、叶轮转速、叶片宽度及叶片偏角作为试验因素,将抛撒距离和土壤集中率作为评价指标,进行单因素和正交旋转组合仿真试验,探究因素对抛土起垄机构作业性能的影响。最后利用Design-Expert数据处理软件对仿真数据进行分析,得到作业最优组合参数,并将最优参数组合来制作样机进行平台试验。结果通过仿真试验与平台试验对比,得出最佳起垄组合参数:导向罩角度为30°,叶轮转速为275 r/min,叶片宽度为82 mm、叶片偏角为–7.5°;罩角度为62°,叶轮转速为314 r/min,叶片宽度为82 mm、叶片偏角为–7.5°,最终得到仿真结果中土壤集中度分别为73%和81%,抛撒距离为2081.29 mm和979.2 mm,平台试验验证结果在合理区间范围内。结论根据仿真与平台试验结果的对比,得到机构抛土效果满足蕉园的起垄要求的最佳参数组合,为“超宽窄行”蕉园起垄机械设计提供了参考依据。 展开更多
关键词 抛土起垄机构 离散元法 正交试验 平台试验
下载PDF
菌草穴盘苗取投苗装置设计与试验分析
18
作者 叶大鹏 青家兴 +3 位作者 吴逸腾 赖鸿康 翁海勇 李庆 《中国农机化学报》 北大核心 2024年第10期9-16,53,共9页
目前菌草穴盘苗移栽过程中缺乏自动取投苗装置,通过分析取投苗装置的工作原理,建立运动学模型并优化结构参数,研发一种六杆式取投苗装置。根据菌草穴盘苗钵体的抗压力学特性、取投苗装置的基本约束与空间约束,优化分析得到各杆件的结构... 目前菌草穴盘苗移栽过程中缺乏自动取投苗装置,通过分析取投苗装置的工作原理,建立运动学模型并优化结构参数,研发一种六杆式取投苗装置。根据菌草穴盘苗钵体的抗压力学特性、取投苗装置的基本约束与空间约束,优化分析得到各杆件的结构参数,建立虚拟样机得到仿真轨迹和运动学参数。进一步研制样机,结合高速摄像技术获取取投苗装置的实际运动轨迹,对比两种轨迹的一致程度,验证装置设计的合理性。以取投“绿洲一号”菌草穴盘苗为例,将主动杆转速、送苗装置倾斜角以及钵体含水率作为试验因素,取苗成功率、投苗成功率作为响应指标,开展三因素三水平正交试验。试验结果表明,在主动杆转速为30 r/min、钵体含水率为60%、送苗装置倾斜角为50°时,取投苗的效果最优。重复试验表明,在最优因素水平下,取苗成功率与投苗成功率分别为95.31%和93.4%。 展开更多
关键词 菌草穴盘苗 取投苗装置 六杆装置 自动化移栽设备
下载PDF
基于GaAs E/D PHEMT工艺的Ku波段双通道幅相控制多功能芯片
19
作者 徐伟 赵子润 +1 位作者 刘会东 李远鹏 《半导体技术》 CAS 北大核心 2024年第6期575-579,588,共6页
基于GaAs增强/耗尽型赝配高电子迁移率晶体管(E/D PHEMT)工艺设计了一款14~18 GHz的双通道多功能芯片。芯片集成了单刀双掷(SPDT)开关、6 bit数控移相器、4 bit数控衰减器和增益补偿放大器。采用正压控制开关以减小控制位数;优化移相、... 基于GaAs增强/耗尽型赝配高电子迁移率晶体管(E/D PHEMT)工艺设计了一款14~18 GHz的双通道多功能芯片。芯片集成了单刀双掷(SPDT)开关、6 bit数控移相器、4 bit数控衰减器和增益补偿放大器。采用正压控制开关以减小控制位数;优化移相、衰减和放大等电路拓扑结构,以获得良好的幅相特性;采用紧凑布局、双通道对称的版图设计,以实现小尺寸和高性能。测试结果表明,+5 V电压下,接收通道增益大于3 dB,1 dB压缩点输出功率大于8 dBm;发射通道增益大于1 dB,1 dB压缩点输出功率大于2 dBm;64态移相均方根误差小于2.5°,16态衰减均方根误差小于0.3 dB,芯片尺寸为3.90 mm×2.25 mm。该多功能芯片可实现对射频信号幅度和相位的高精度控制,可广泛应用于微波收发模块。 展开更多
关键词 双通道 多功能芯片 增强/耗尽型赝配高电子迁移率晶体管(E/D PHEMT) 单刀双掷(SPDT)开关 数控移相器 数控衰减器
下载PDF
Geometry and 3D seismic characterisation of post-rift normal faults in the Pearl River Mouth Basin,northern South China Sea
20
作者 Yuanhang Liu Jinwei Gao +2 位作者 Wanli Chen Jiliang Wang Umair Khan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第4期25-39,共15页
Based on high-resolution 3D seismic data acquired in the Pearl(Zhujiang)River Mouth Basin of the northern South China Sea,this study investigated the geometry,spatial extension,and throw distribution of the post-rift ... Based on high-resolution 3D seismic data acquired in the Pearl(Zhujiang)River Mouth Basin of the northern South China Sea,this study investigated the geometry,spatial extension,and throw distribution of the post-rift normal fault through detailed seismic interpretation and fault modeling.A total of 289 post-rift normal faults were identified in the study area and can be classified into four types:(1)isolated normal faults above the carbonate platform;(2)isolated normal faults cutting through the carbonate platform;(3)conjugate normal faults,and(4)connecting normal faults.Throw distribution analysis on the fault planes show that the vertical throw profiles of most normal fault exhibit flat-topped profiles.Isolated normal faults above the carbonate platform exhibit roughly concentric ellipses with maximum throw zones in the central section whereas the normal faults cutting through the carbonate platform miss the lowermost section due to the chaotic seismic reflections in the interior of the carbonate platform.The vertical throws of conjugate normal faults anomalously decrease toward their intersection region on the fault plane whereas the connecting normal faults present two maximum throw zones in the central section of the fault plane.According to the symmetric elliptical distribution model of fault throw,an estimation was made indicating that normal faults cutting through the carbonate platform extended downward between-1308 s and-1780 s(two-way travel time)in depth and may not penetrate the entire Liuhua carbonate platform.Moreover,it is observed that the distribution of karst caves on the top of the carbonate platform disaccord with those of hydrocarbon reservoirs and the post-rift normal faults cutting through the carbonate platform in the study area.We propose that these karst caves formed most probably by corrosive fluids derived from magmatic activities during the Dongsha event,rather than pore waters or hydrocarbons. 展开更多
关键词 Post-rift normal faults fault throw Karst caves Corrosive fluids Pearl River Mouth Basin South China Sea
下载PDF
上一页 1 2 113 下一页 到第
使用帮助 返回顶部