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Search Results: 1 - 10 of 181933 matches for " 陈益丹 "
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基于ATP-EMTP的大型电力系统暂态稳定仿真
,,艾芊,,付慧,李长
电力系统自动化 , 2006,
Abstract: 提出采用电磁暂态仿真软件EMTP的ATP版本作为大规模电力系统的暂态稳定仿真工具,用以解决机电暂态仿真程序所不能仿真的电力电子的快速暂态过程、非线性元件模型和系统不对称运行。通过对固定串补不同模型的分析,说明采用ATP-EMTP进行暂态稳定计算的必要性。通过对江苏苏北电网的ATP-EMTP和电力系统分析综合程序(PSASP)的潮流和暂态稳定的对比试验,验证了用ATP-EMTP进行大规模电力系统暂态稳定仿真的可行性。
全国水利普查空间信息系统的若干关键技术
蔡阳,谢文君,付静,,,成建国
测绘学报 , 2015, DOI: 10.11947/j.AGCS.2015.20140476
Abstract: 针对全国水利普查中对象信息获取、数据资源管理、成果质量控制和项目组织实施等主要难题,提出了“基础数据支撑、数据模型先导、智能工具保障、技术管理融合”的总体技术路线,介绍了全国水利普查空间信息系统的面向对象水利数据建模、数字河流获取、规则约束采集处理、多主题数据应用等关键技术。
基于SVM与相似日的短期电力负荷预测
于龙,,王昕,李立学,周荔,洪涛
电工技术学报 , 2013,
Abstract: 对受多种不确定性因素影响的短期电力负荷预测,提出了一种基于模糊聚类选取相似日的短期电力负荷预测方法。该方法首先针对气象类型的不确定性因素,将气象因素细分为气温、气压、风速、阴雨等情况,和星期类型、日期类型一起构成相似日的影响因素,通过模糊规则建立模糊系数特征映射表,实现了影响因素的量化。然后再采用模糊聚类方法进行分类,根据聚类水平选取相似日,从而达到减少样本数量,加快选取速度的目的。接着针对获取的相似日负荷数据中含有非高斯噪声的问题,利用小波变换获取其低频分量,从而有效地消除了非高斯噪声的影响。再采用PSO优化的支持向量机实现短期电力负荷低频部分的预测,采用加权平均方法实现高频部分的预测,提高了预测精度。最后利用上海市某电网的负荷数据进行应用研究,不但在平时日,而且在周末和节假日,都取得了较好的预测效果。
考虑动态无功支持的双馈风电机组高电压穿越控制策略
徐海亮, 章玮, 建生,,
中国电机工程学报 , 2013,
Abstract: 讨论电网电压骤升时双馈风电机组网侧和转子侧变流器有功、无功功率的分配原则,给出有功、无功电流的极限表达式,提出一种能有效提供动态无功支持的高电压穿越(highvoltageride-through,HVRT)实现方案。在机组端电压骤升至1.1倍标称值以上时,该方案一方面控制网侧变流器输出与电压骤升幅度相匹配的无功电流,实现母线电压的稳定;另一方面通过优化转子侧变流器有功、无功电流设定,使双馈感应发电机工作在无功支持模式,优先向故障电网输出一定的感性无功功率。仿真和实验结果表明,该控制方案不仅能确保电网电压骤升期间双馈风电机组的不脱网运行,还能对故障电网提供一定的动态无功支撑,协助电网电压快速恢复,利于其它并网负载的安全运行。
基于低占空比的机会汇聚树路由协议
,晓江,黄骏杰,尹小燕,房鼎
计算机应用 , 2013,
Abstract: ?针对无线传感器网络(wsn)中存在节点剩余能量不足而导致的路由失效问题,提出一种基于低占空比的汇聚树机会路由算法ctor。在ctor中,首先根据网络的传输质量需求确定路由候选节点集;然后,节点以广播方式向所有候选节点传输数据包,收到数据包的候选节点再以一定概率转发该数据包,转发成功的候选节点即为选定的路由节点。概率的引进保证了高数据传输质量与轻网络负载;同时,网关节点发送时间同步控制信息以达到全网时间同步的目的;节点根据固定占空比进行休眠切换,以减少节点的能量消耗,延长网络的生存周期。仿真实验表明,基于低占空比的协议可有效地避免网络空洞问题,延长网络的生存周期;同时,机会性的转发可以有效地提高数据包的成功接收率,降低网络的丢包率。
国人膝关节前外侧韧带的解剖学研究
Anatomical study on anterolateral ligament in a Chinese population

蔡江瑜,金文赫,盛旦,
- , 2017, DOI: 10.7507/1002-1892.201707042
Abstract: 目的 解剖研究国人膝关节前外侧韧带(anterolateral ligament,ALL),探讨 ALL 结构特征,为临床上 ALL 损伤的诊治,特别是 ALL 重建手术的开展提供参考。 方法 选用成年尸体膝关节标本 16 具,男、女各 8 具,左、右膝各 8 具;供体年龄 57~84 岁,平均 73.5 岁。根据标准入路进行解剖,并对 ALL 进行定性和定量的描述。 结果 16 具标本中 12 具可见 ALL,出现率为 75.0%。它起自股骨外上髁,起点位于外侧副韧带(lateral collateral ligament,LCL)的起点近端后方,其走行越过 LCL 表面或与之并行,韧带中段与外侧半月板体部边缘紧密相连,止点位于 Gerdy 结节和腓骨头之间,止点中心与 Gerdy 结节中心以及腓骨头最外侧缘的距离分别为(23.9±3.3)、(23.8±4.0)mm。膝关节中立位屈曲 0° 和 60° 时 ALL 长度分别为(44.8±5.1)、(47.8±5.5) mm,比较差异无统计学意义( t=14.071, P=0.000),在膝关节屈曲 60° 合并内旋时 ALL 较紧张。根据男女进行分组比较,屈曲 0° 和 60° 时男性 ALL 长度均显著大于女性( t=2.920, P=0.015; t=2.806, P=0.019);其余测量指标比较,差异无统计学意义( P>0.05)。 结论 ALL 是一条位于膝关节前外侧的独立非等长韧带结构,其长度存在性别差异。ALL 在维持膝关节旋转稳定性方面发挥一定作用,临床上应引起足够重视。
Objective To make further exploration of the structure characteristics of anterolateral ligament (ALL) and provide clinical reference for diagnosis and treatment of ALL injury, especially for ALL reconstruction through anatomical study of ALL in a Chinese population. Methods Sixteen cadaveric knees, including 8 left knees and 8 right knees with sex ratio of 1∶1 and a mean age of 73.5 years (range, 57-84 years), were dissected to reveal the ALL through a standard approach. A qualitative and a quantitative characterizations of the ALL were performed. Results ALL was seen in 75.0% of the specimens, originating on the lateral femoral epicondyle, proximal and posterior to the lateral collateral ligament (LCL). It coursed on LCL or was parallel to LCL, anterodistally to its anterolateral tibial attachment approximately midway between the center of the Gerdy’s tubercle and the lateral margin of the fibular head. A strong connection was observed between the middle part of the ALL and the periphery of the meniscal body of the lateral meniscus. The distance between the center of the insertion and Gerdy’s tubercle was (23.9±3.3) mm; and the distance between the center of the insertion and the lateral margin of the fibular head was (23.8±4.0) mm. The ALL length at 0° and 60° flexion and neutral knee rotation were (44.8±5.1) mm and (47.8±5.5) mm respectively ( t=14.071, P=0.000), and the ligament had its great extend at 60° of knee flexion and internal rotation. Furthermore, the ALL length at 0° and 60° flexion of males were both significantly higher than those of females ( t=2.920, P=0.015; t=2.806, P=0.019), while other measurements differences were significant between males and females ( P>0.05). Conclusion ALL is an independent and a non-isometric ligament located in the anterolateral area to the knee, of which the length is different between males and females. ALL plays a role
一种温度自适应无线传感网络时间同步方法
金梦?,晓江?,房鼎,汤战勇?,刘晨?,,王薇?
软件学报 , 2015, DOI: 10.13328/j.cnki.jos.004792
Abstract: 无线传感器网络节点中的廉价晶振极易受到温度、电压、湿度等工作环境因素的影响.节点晶振的这一特性,为室外大规模无线传感器网络时间同步技术带来了两方面的挑战:(1)过高的通信开销;(2)精度与能耗之间的不平衡.针对以上问题,提出了一种基于温度感知的、自适应的无线传感器网络时间同步算法.该算法能够依赖本地温度信息对节点时间频偏进行估计及补偿,在保证算法同步精度的同时,降低了网络通信开销.除此之外,提出一种动态同步周期调节机制,使得算法能够根据当前环境温度变化情况对节点同步周期进行动态调节,从而达到了能耗与精度之间的平衡.大量仿真实验结果表明:所提出的时间同步算法可将通信能耗降低至传统同步算法的10%;且在环境温度不断变化的情况下,80%的频偏估计值其误差小于0.5ppm.故,所提出的时间同步方法能够有效地适用于室外环境下部署的大规模无线传感器网络.
超声联合靶向阳离子微泡介导Ang-1基因转染改善兔缺血心肌功能 Ultrasound Combined with Targeted Cationic Microbubbles Mediated Ang-1 Gene Transfection Improves the Cardiac Function of Rabbit with Myocardial Infarction
邓倾,张丙宏,,,思楷,杨远婷,周青
- , 2018,
Abstract: 目的:构建靶向阳离子微泡作为基因载体,增强超声靶向微泡破坏(UTMD)介导血管新生基因转染家兔心肌组织的效率,从而提高心肌梗死的疗效。方法:构建家兔心肌梗死模型,制备细胞间黏附分子(ICAM)-1靶向阳离子微泡(TCMB)和非靶向普通阳离子微泡(CMB),以生理盐水为空白对照(Control),将家兔分为3组:TCMB治疗组,CMB治疗组和Control组,在UTMD作用下分别介导血管生成素-1(Ang-1)基因转染家兔心肌组织,比较三组转染效率及心功能。结果:CMB与TCMB的粒径无明显差异[(2.9±1.9)μmvs(3.1±2.1)μm,P>0.05],二者表面电位分别为(+31.3±3.9)mV和(+22.0±2.4)mV(P<0.01),每千万个微泡的载基因量分别为(3.3±0.7)μg和(4.0±0.9)μg(P<0.05)。转染治疗后3d,TCMB组的Ang-1基因表达高于CMB组,CMB组高于Control组(均P<0.05)。与心梗后2d相比,转染治疗后28d,Control组左室射血分数LVEF进一步减低[(44±10)%],而CMB组和TCMB组均有所改善,但以TCMB组显著[(59±7)%vs(54±8)%,P<0.05]。结论:ICAM-1靶向阳离子微泡能增加载基因能力及靶向性,提高UTMD介导Ang-1基因转染的效率,改善兔缺血心肌功能
正常人群步行足偏角与年龄特征分析
Analysis of the relevance of age and toe out angle of normal adults' gait

顾琳燕,邱华平,张晟宇,,许瑛,金肖青,宁钢民
- , 2018, DOI: 10.7507/1001-5515.201606082
Abstract: 老年人群由于运动能力退化及受到疾病的影响,容易导致步态异常,而异常步态通常会增加老年人的跌倒风险,带来严重伤害。本文重点对正常无运动功能障碍人群的步态运动学参数进行了研究分析,目的是为了研究不同年龄阶段步态参数的特征,探索步态参数在运动机能评估和临床诊断中的作用。本研究基于电子步道采集步态数据,对足偏角和足间夹角等一系列特征以及这些特征与受试者年龄、性别等因素的相关性进行了定量分析。研究结果表明,大部分受试者正常步行时呈正向步态,足偏角会随着年龄的增长而变大,在中青年期变化缓慢,但进入老年后(>60 岁)左足偏角和足间夹角明显升高,变化产生的差异具有统计学意义,研究结果还提示足间夹角是一种普适性强的步态参数。通过本文的研究结果提示,对足偏角进行定量分析有望成为一种对人体下肢运动能力评估及膝关节疾病诊断的便捷、有效的方法。
Due to the decline of motor ability and the impact of the diseases, abnormalities in gait is common in the elderly population, which will raise the risk of fall and cause serious injury. This study focuses on the analysis of the gait kinematics parameters of normal adults’ gait, aiming to investigate the characteristics of gait parameters in different age groups and to explore the role of gait parameters in motor function assessment and clinical diagnosis. Based on the gait data gained by electronic walkway, the relationship among the toe out angles and their correlation with age and gender etc. were quantitatively analyzed. The results show that most normal subjects walk with positive toe out angles, and the angles increase with age. Such changes are slow in the young and middle age groups. However, the elevations of the left out toe angle and the angles between the feet are statistically significant after entering elder age ( >60 years). The results also suggest that the angle between the feet is a kind of practical gait parameter for varying applications. This study concludes that feet angle analysis is potential to provide a convenient and quantitative tool for the assessment of lower limb motor ability and the diagnosis of knee joint diseases.
教育生态理念指导下的中小学生幸福教育
Happiness Education for Primary and Middle School Students under the Guidance of Education Ecological Ideas
 [PDF]


Vocational Education (VE) , 2012, DOI: 10.12677/VE.2012.12009
Abstract:

当前,在我国中小学教育中学生的幸福教育存在着许多误区,如享乐主义、功利主义、虚荣心等。如果这些问题不能及时得到解决,将会给我国的教育事业带来很多的负面影响。现从教育生态学的视角对中小学生的幸福教育进行探究,提出建议,希望对当下中小学生的幸福成长有所帮助。

At present, there exists much misunderstanding in the happiness education for primary and middle school students in our country, such as hedonism, utilitarianism, vanity, etc. It will bring about lots of negative effects to the education in our country if these problems can not be solved in time. This article attempts to investigate the happiness education for primary and middle school students from the perspective of education ecology and put forward suggestions to the primary and middle school students so as to they grow up happily.

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