Results 51 to 60 of about 18,901 (182)

Design and Implementation of the Vehicle Management System for a Company [PDF]

open access: yes, 2015
随着信息时代的到来,工作效率日益提高,车辆管理部门的信息化建设势在 必行;同时中央发布的机构改革、企业改制等政策影响,要求车辆部门精兵简政、 减少日常经费开支、充分合理利用现有资源;社会对车辆管理部门也提出了更高 的要求,为了适应新形势下某公司对车辆管理提出的高要求,推进车辆管理体系 建设、提高车辆管理集约化、规范化和标准化,某公司的车辆管理系统应运而生, 帮助解决某公司车辆管理的实际问题,节约管理成本,提高工作效率。 本文探讨某公司车辆管理系统的设计与实现相关技术,利用GPS全球定位 系统 ...
陈云腾
core  

压气式SF6断路器动态运动特性的研究

open access: yesGaoya dianqi, 1983
本文分析了压气式SF6断路器的静态与动态运动特性的区别,考虑了电弧电流对运动特性的影响,引进了电弧截面影响系数δ和电弧温度系数Ω。然后应用焓流理论求取了电弧面积,导出了负载下电气室气体密度,压力特性及断路器分闸特性计算式。最后以LW—220落地箱式SF6断路器为例进行了计算,并与试验结果作了比较。
施文耀
doaj  

黄河干流头道拐水文站水沙运动特征及影响因素

open access: yesShuitu Baochi Xuebao, 2021
为明确黄河干流头道拐水文站水沙运动过程、变化趋势及运动状态特征,以2006—2018年黄河干流头道拐水文站水沙数据为基础,基于累积距平法、R/S极差分析法、河道来沙系数与不协调度等研究方法,对头道拐水文站水沙运动过程进行系统分析。结果表明:头道拐水文站年际间径流与输沙量和年内月均径流与输沙量变化趋势均呈现良好的一致性,但两者的季节性差异特征显著,且输沙量的显著性较径流更突出;冬季径流与输沙量变化趋势同步性相比其他季节较差 ...
赵水霞   +6 more
doaj  

Centering geospatial data uncertainty and the potential for injustice in pastoralist rangeland conservation prioritization

open access: yesConservation Biology, EarlyView.
Abstract Procedural, distributional, recognitional, and epistemic justice aspects of conservation interventions are well documented in contexts where pastoralism is a key livelihood and way of life. Geospatial analyses and representations of wildlife conservation and restoration that are increasingly applied in pastoralist rangeland socioecological ...
Ryan R. Unks
wiley   +1 more source

Assessing differences among elasmobranch nurseries to aid conservation based on a genomics framework

open access: yesConservation Biology, EarlyView.
Abstract Elasmobranch nurseries often differ in environmental conditions, demographics, and use patterns. These differences affect the distribution of genetic variation among nurseries. However, conservation and management strategies often fail to account for such differences because they are difficult to characterize.
Dominic G. Swift   +8 more
wiley   +1 more source

A precise two dimensional tracking servo system based on CANopen bus [PDF]

open access: yes, 2016
在航空航天、民用、军事领域都起到重要作用的双自由度转台是一种复杂的集光机电一体化的设备,整体设备的精度和性能将直接受其性能的影响。因此,如何同时获取良好的动态性能、较小的体积重量、足够的旋转扭矩以及较小的噪声振动是本文亟需解决的问题。 本文根据中波红外光谱分析技术和长波红外成像双波段结合的红外光谱仪设备技术要求,设计了双自由度转台。该转台采用美国COPLEY公司的CANPCI卡作为CAN通讯卡,两台COPLEY驱动器分别作为主机与从机直接驱动作为执行机构的两台交流伺服电机,实现两个自由度上的运动 ...
欧阳琪楠
core  

Emerging applications of large language models in ecology and conservation science

open access: yesConservation Biology, EarlyView.
Abstract Large language models (LLMs) mark a major development in artificial intelligence, with potentially transformative implications for ecology and conservation science. Built on advanced deep‐learning architectures, these models can support a wide range of tasks. We reviewed emerging applications of LLMs, drawing on the wider scientific literature
Christos Mammides   +5 more
wiley   +1 more source

Research of test methods of pressure sensor’s dynamic characteristics [PDF]

open access: yes, 2012
在压力传感器动态特性测试实验中,激波管阶跃压力标准产生的阶跃压力有压力幅值范围广、上升时间短等特点,但是它的阶跃压力维持时间也很短(一般为5ms-10ms),若待测压力传感器的固有频率较低(小于2KHz),则无法使用激波管进行压力传感器动态测试。且激波管结构复杂、价格较贵,一般单位和个人进行压力传感器动态特性标定都必需要到专业的标定单位进行标定,给动态特性校准带来困难。 本文提出一种基于大气压产生阶跃压力的压力传感器动态特性测试系统,该系统结构简单,价格便宜,阶跃压力维持时间可以达到无限大 ...
林俊阳
core  

Motion Simulation of a New High Overload Flight Simulator [PDF]

open access: yes, 2017
提出一种新型的基于绳牵引并联机器人技术的飞行模拟器,针对其大过载机动特性进行仿真分析。首先根据绳牵引并联机器人理论,设计了9根绳牵引具有6自由度的运动平台;通过建立平台动力学模型,设计了对干扰项进行补偿的前馈PD控制率;其中前馈项主要确保动态过程中绳索处于张紧状态。进一步给出了系统控制稳定性分析;并以大过载机动和单自由度俯仰振荡运动为例进行了数值仿真。分析结果表明,在大过载机动情况,瞬时正加速度超过4 g,平台位置能够迅速衰减并稳定;基于绳拉力前馈,可以避免绳索松弛,能够满足飞行员过载训练 ...
刘亚辉, 王晓光
core   +1 more source

Learning Styles, Engagement and Anxiety in AI‐Mediated Writing: A Multimodal Feedback Study

open access: yesInternational Journal of Applied Linguistics, EarlyView.
ABSTRACT Artificial intelligence (AI) tools now permeate English academic writing. However, evidence on how feedback modalities align with student differences and with psychological mechanisms remains limited. Prior work often reduced learning styles to simple matches with delivery modes and treated learning engagement and writing anxiety as peripheral.
Yi Ren   +3 more
wiley   +1 more source

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