期刊文献+
共找到638篇文章
< 1 2 32 >
每页显示 20 50 100
基于Bursa模型的地球重力场模型2008高程异常误差算法
1
作者 刘猛 章思亮 +4 位作者 朱永峰 张亮 赵伟 栾丽明 陆玉霞 《济南大学学报(自然科学版)》 CAS 北大核心 2024年第4期439-444,共6页
针对地球重力场模型2008(EGM2008)根据点位经纬度求得的高程异常精度较差,且测区内校正用已知点难以就近获得的问题,提出一种以Bursa模型求解EGM2008高程异常误差的算法;基于Bursa模型可进行严密高程转换的特点,利用测区外已知点求解的... 针对地球重力场模型2008(EGM2008)根据点位经纬度求得的高程异常精度较差,且测区内校正用已知点难以就近获得的问题,提出一种以Bursa模型求解EGM2008高程异常误差的算法;基于Bursa模型可进行严密高程转换的特点,利用测区外已知点求解的转换参数对测量点进行EGM2008高程异常误差值解算;以验算实例和不同区域工程实例对比的方式对该算法进行验算,结果表明:所提算法解算的高程异常误差值可作为EGM2008高程异常误差的修正值,利用远距离已知点校正高程异常可得到图根级精度的高程成果,且能适应不同地形、地势的工程测量要求。 展开更多
关键词 地球重力场模型2008 高程异常 bursa模型 误差修正
下载PDF
Large Painful Bursae at Abeche Hospital: Epidemiological, Clinical, Therapeutic and Evolutionary Aspects
2
作者 Vadandi Valentin Mahamat Ali Mahamat +6 位作者 Minguemadji Allah Siyangar Temga Ouang Michael Vounouzia Barthelemy Ndormadjita Allah Siyangar Abdelmahamoud Chene Konan Paul Gerard Rimtebaye Kimassoum 《Open Journal of Urology》 2024年第5期312-316,共5页
Introduction: Acute large bursae (ALB) are a frequent reason for emergency consultations. The aim of this study was to investigate the prevalence, clinical course, treatment and evolution of ALB at Abeche University H... Introduction: Acute large bursae (ALB) are a frequent reason for emergency consultations. The aim of this study was to investigate the prevalence, clinical course, treatment and evolution of ALB at Abeche University Hospital. Patients and Method: This was a 45-month cross-sectional study from January 2020 to September 2023. Male patients of any age who had been admitted to and treated for acute large bursae at the Abeche University Hospital were included. Sociodemographic, clinical and therapeutic variables were studied. Results: Acute large bursae accounted for 7.92% of emergency admissions. The average age was 39.40 years. 60.27% of patients came from rural areas. The average consultation time was 4 days, ranging from a few hours to 18 days. The main reason for consultation was pain. Strangulated inguino-scrotal hernia was the most common, followed by acute orchi-epididymitis, accounting for 41.8% and 26% of cases respectively. Traditional treatment prior to consultation was attempted in 13.7% of cases. All patients were treated as emergencies, 41 of whom had received medical treatment. Of the patients treated surgically, orchidopexy was performed in all. Parietal suppuration and anaemia occurred in 6.2% and 4.8% of cases respectively. Conclusion: A accounts for a significant proportion of our emergency care activity. However, patients are seen with a delay, which jeopardises the functional prognosis of the testicle and intestine. 展开更多
关键词 Acute Large bursa Orchiepididymitis TORSION Spermatic Cord CHU-A
下载PDF
Bursa的3参数模型与7参数模型的适用性研究 被引量:17
3
作者 于彩霞 黄文骞 樊沛 《测绘科学》 CSCD 北大核心 2008年第2期96-97,共2页
对于Bursa模型,7参数模型相对于3参数模型更严密,但存在局部区域内参数不稳定且难于确保参数在控制点外围区域的转换精度。本文利用仿真试验检验3参数模型与7参数模型的精度、稳定性与所用公共点的控制范围的关系,得出了模型的选择方法。
关键词 bursa模型 坐标转换 转换参数
下载PDF
基于谱修正迭代的Bursa模型 被引量:3
4
作者 侯东阳 张书毕 +1 位作者 万亚豪 刘玉婵 《海洋测绘》 2011年第5期15-17,共3页
利用Bursa模型进行空间直角坐标转换时,求解的过程中如果法方程的系数矩阵是病态,则求得的转换参数并不可靠。在谱修正迭代法的基础上,推导了基于谱修正迭代的Bursa模型公式,通过算例可知该方法可有效改善病态矩阵对坐标转换的影响,其... 利用Bursa模型进行空间直角坐标转换时,求解的过程中如果法方程的系数矩阵是病态,则求得的转换参数并不可靠。在谱修正迭代法的基础上,推导了基于谱修正迭代的Bursa模型公式,通过算例可知该方法可有效改善病态矩阵对坐标转换的影响,其坐标转换精度比Bursa模型高。 展开更多
关键词 坐标转换 谱修正迭代法 bursa模型 外推精度
下载PDF
基于Bursa加权模型的格网坐标转换 被引量:6
5
作者 郭充 吕志平 +1 位作者 于兴超 徐基刚 《测绘科学技术学报》 北大核心 2009年第2期86-88,92,共4页
2000国家大地坐标系(CGCS2000)在我国启用将使得许多测绘成果的坐标面临转换,需要研究具有较高精度的坐标转换方法。由于我国天文大地网存在较大的局部系统差和累积误差,采用Bursa模型完成向高精度地心坐标系的转换时往往还剩余较大的... 2000国家大地坐标系(CGCS2000)在我国启用将使得许多测绘成果的坐标面临转换,需要研究具有较高精度的坐标转换方法。由于我国天文大地网存在较大的局部系统差和累积误差,采用Bursa模型完成向高精度地心坐标系的转换时往往还剩余较大的残差。为了提高转换精度,这里提出了一种方法,通过将转换区域划分为小的格网单元,然后利用Bursa模型、加权平均模型计算得到每个格网节点的坐标转换改正量;最后再通过格网内插得到其中任意位置的坐标转换改正量,从而完成坐标转换。该方法保证了局部的细致拟合和整体上的连续。试验结果表明,该方法可使天文大地网的局部系统差和累积误差得到有效地控制,避免了转换后较大残差的出现。 展开更多
关键词 bursa模型 加权平均模型 格网 坐标转换 改正量
下载PDF
Bursa转换模型七参数严密解算方法研究 被引量:10
6
作者 刘仁钊 段文贵 张玉堂 《资源环境与工程》 2010年第4期416-418,423,共4页
针对现行教材中Bursa线性转换模型只适合小旋转角的情况,提出了基于中心化后Bursa转换模型七参数严密解算方法,迭代过程无需计算搜索步长λ。通过实例计算表明,该方法数值计算正确,适用于任意两空间坐标系之间的严密转换。
关键词 bursa转换模型 中心化坐标 最小二乘法 迭代计算
下载PDF
BURSA模型应用于BJ54与WGS84坐标转换的讨论 被引量:7
7
作者 吴吉贤 杨志强 +1 位作者 张耀文 杜海燕 《高原地震》 2006年第3期32-36,共5页
WGS84与BJ54坐标的转换一直是测量领域基础性工作,并在测量工区范围内有极其广泛的应用。本文以Bursa模型作为它们之间转换的理论依据,并以浙江某一区域的一级GPS点的坐标值进行转化,获得了很高的精度。
关键词 bursa(布尔莎) 坐标转换 七参数法
下载PDF
利用简化的BURSA-WOLF公式进行GPS坐标成果转换及精度分析 被引量:3
8
作者 李秀海 杜国明 《黑龙江工程学院学报》 CAS 2004年第3期20-22,共3页
通过对BURSA-WOLF公式进行简化,得到两种简化的BURSA-WOLF模型。简化公式具有形式简单、直观、转换参数少、编制程序简单等优点。利用简化的公式对某城市四等控制网的GPS观测成果进行坐标转换和精度分析,结果表明,两种公式具有不同的转... 通过对BURSA-WOLF公式进行简化,得到两种简化的BURSA-WOLF模型。简化公式具有形式简单、直观、转换参数少、编制程序简单等优点。利用简化的公式对某城市四等控制网的GPS观测成果进行坐标转换和精度分析,结果表明,两种公式具有不同的转换精度,适用不同的GPS测量及应用。 展开更多
关键词 简化的bursa-WOLF公式 坐标转换 GPS
下载PDF
一种改进的Bursa模型在坐标转换中的应用 被引量:1
9
作者 陈博 黄翔 +1 位作者 李泷杲 邢宏文 《机械制造与自动化》 2015年第3期87-89,共3页
在数字化测量中经常面临坐标转换的问题,转换参数在很大程度上影响着最终测量精度。在采用bursa模型求取转换参数时一般是通过3个以上公共点利用最小二乘法求取,但其中的系数矩阵往往是病态的,使转换参数并不可靠。现采用7参数法,对布... 在数字化测量中经常面临坐标转换的问题,转换参数在很大程度上影响着最终测量精度。在采用bursa模型求取转换参数时一般是通过3个以上公共点利用最小二乘法求取,但其中的系数矩阵往往是病态的,使转换参数并不可靠。现采用7参数法,对布尔沙模型进行泰勒展开,建立了适用于大旋转角的线性化坐标系转换模型。 展开更多
关键词 坐标转换 最小二乘 bursa模型 转换参数
下载PDF
基于改进的Bursa模型坐标转换的探讨 被引量:1
10
作者 刘亚东 仇秀梅 《测绘与空间地理信息》 2015年第10期88-91,共4页
针对目前空间坐标转换方法,提出一种改进的Bursa模型,利用模拟数据的计算与分析,对该方法进行坐标转换的收敛与迭代情况,以及参数估计准确性做了相关探讨,表明该方法可以求解任意欧拉角的坐标系转换。
关键词 bursa模型 坐标转换 七参数
下载PDF
Mortality rates from a Nigerian isolate of the <i>Infectious Bursa Disease Virus</i>and passive haemagglutination antibody titer that protects chicks against challenge with the virus isolate 被引量:3
11
作者 Maduike C. O. Ezeibe John O. A. Okoye +4 位作者 Temitope M. Ogunniran Paul C. Animoke Ijeoma J. Mbuko Ijeoma A. Nwankwo Augustine A. Ngene 《Health》 2013年第9期1355-1359,共5页
To determine passive haemagglutination (PHA) antibody titer that would protect chicks against Nigerian isolates of the Infectious Bursa Disease Virus (IBDV), five groups of chicks aged 30 days which had different anti... To determine passive haemagglutination (PHA) antibody titer that would protect chicks against Nigerian isolates of the Infectious Bursa Disease Virus (IBDV), five groups of chicks aged 30 days which had different antibody titers were challenged with a Nigerian isolate of virulent IBDV. Mortality rates of the different groups were plotted against their respective mean PHA antibody titers. A group with zero antibody titer had a mortality rate of 75% while those with PHA antibody titers of 185.6, 243.2, 256 and 307.2 had mortality rates of 40%, zero, zero and zero respectively. Linear equation generated for a line of best fit of the graph of mortality rates of the chicks on their IBD antibody titers gave antibody titer (X) at which mortality (Y) would be zero as 300. A mortality of 75% and the high antibody level needed to protect chicks suggest that the isolate may be a hypervirulent strain. 展开更多
关键词 Protective Antibody Titer Hypervirulent INFECTIOUS bursa Disease VIRUS Strain NIGERIAN ISOLATE
下载PDF
Bursa非线性转换模型7参数的粒子群解法 被引量:2
12
作者 杨星 朱大栋 +1 位作者 赵钢 李志清 《大地测量与地球动力学》 CSCD 北大核心 2012年第5期86-90,94,共6页
针对Bursa非线性转换模型7参数求解中广泛使用的最小二乘法存在的非线性方程矩阵病态问题、初值选取困难问题以及求解收敛性等问题,提出了一种Bursa非线性转换模型7参数求解的粒子群算法。实例证明:该算法计算结果精确度高,且适合于大... 针对Bursa非线性转换模型7参数求解中广泛使用的最小二乘法存在的非线性方程矩阵病态问题、初值选取困难问题以及求解收敛性等问题,提出了一种Bursa非线性转换模型7参数求解的粒子群算法。实例证明:该算法计算结果精确度高,且适合于大旋转角。 展开更多
关键词 bursa模型 7参数 非线性转换 粒子群算法 空间坐标
下载PDF
基于Bursa-Wolf模型的坐标转换工具设计
13
作者 宋超 原菲菲 +1 位作者 尚姣 士子远 《地理空间信息》 2014年第2期139-140,148,共3页
选取Bursa-Wolf模型作为转换模型,采用QR矩阵求解模型转换参数,实现了坐标系转换算法;研发了北京54坐标数据向西安80坐标系统的转换工具。经检验,其转换误差相对精确、数值计算稳定性好。
关键词 bursa-Wolf模型 QR矩阵 数学算法 程序设计
下载PDF
Tribenuron-Methyl Resistant Shepherd's Purse (Capsella bursa-pastoris (L.) Medik.) in Hebei Province of China 被引量:2
14
作者 WANG Gui-qi CUI Hai-lan +4 位作者 ZHANG Hong-jun ZHANG Yan-qiu LIU Xue LI Xiang-ju FAN Cui-qin 《Agricultural Sciences in China》 CAS CSCD 2011年第8期1241-1245,共5页
Shepherd's purse seeds were collected from winter wheat fields and road sides in Hebei Province,China.Their sensitivities to tribenuron-methyl were evaluated in a whole plant dose response assay in the greenhouse.Res... Shepherd's purse seeds were collected from winter wheat fields and road sides in Hebei Province,China.Their sensitivities to tribenuron-methyl were evaluated in a whole plant dose response assay in the greenhouse.Results revealed that HB-1,HB-2,HB-3,HB-4,HB-6,HB-7,HB-17,HB-18,HB-19,HB-20,HB-21,and HB-22 populations were susceptible to tribenuron-methyl characterised by very low GR50 values of about 0.10 g a.i.ha-1.On the other hand,populations HB-15 and HB-16 had moderate resistance to tribenuron-methyl with resistance indices (RI) ranging from 10-100 folds,whilst populations HB-5,HB-8,HB-9,HB-10,HB-11,HB-12,HB-13,and HB-14 expressed high level of resistance to tribenuron-methyl with resistance indices over 100.The proportion of moderate resistance level was about 9.09%,and that of high resistance was about 36.36%. 展开更多
关键词 ALS inhibitor tribenuron-methyl resistance shepherd's purse (Capsella bursa-pastoris (L.) Medik.)
下载PDF
A Comparison of Subacromial Bursae Block, Suprascapular Nerve Block and Interscalene Brachial Plexus Block after Arthroscopic Shoulder Surgery 被引量:1
15
作者 J. Ovesen T. Falstie-Jensen C. Christensen 《Pain Studies and Treatment》 2014年第3期107-112,共6页
Background: The aim of this study was to compare the analgesic efficacy of subacromial bursae block (LA), suprascapular nerve block (SSB), and interscalene brachial plexus block (ISB) after arthroscopic shoulder surge... Background: The aim of this study was to compare the analgesic efficacy of subacromial bursae block (LA), suprascapular nerve block (SSB), and interscalene brachial plexus block (ISB) after arthroscopic shoulder surgery. Methods: 91 patients scheduled to undergo an arthroscopic shoulder acromioplasty under GA in an outpatient setting were included. The patients were prospectively randomized into 4 groups: 1) interscalene brachial plexus block, 2) suprascapular nerve block, 3) subacromial bursae block, 4) control group for comparison. Pain scores (VAS), supplemental analgesia, and side effects were recorded in the recoveryroom, 4 hours and 24 hours after surgery. Results: Group ISB had significantly lower pain scores at rest in the postanesthesia care unit than the SSB group (p = 0.037) and the control group (p = 0.0313). The same results were seen 4 hours follow-up. The LA group had significantly lower pain scores at rest in the postanesthesia care unit than the control group (p = 0.046) and after 4 hours follow-up significantly lower pain scores than both the SSB group (p = 0.021) and the control group (p = 0.037). After 24 hours, there were no differences between the two groups. Conclusion: In this prospective, randomized, blinded study we demonstrated that a single-dose interscalene brachial plexus block (ISB) and a subacromial bursae block (LA) are equal and the most efficient analgesic techniques after arthroscopic shoulder acromioplasty. LA is less expensive, faster and with fewer complications than ISB and therefore we suggest subacromial bursae block is an effective, safe and easy way of postoperative pain reduction after arthroscopic acromioplasty. Level of evidence: Level I. Treatment study. 展开更多
关键词 SHOULDER Surgery Pain RELIEF INTERSCALENE BLOCK SUBACROMIAL bursae BLOCK Suprascapular BLOCK
下载PDF
适用于大区域GNSS手薄的Bursa 7参数的应用与研究
16
作者 侯文才 李存文 +1 位作者 李敏 周强 《地矿测绘》 2018年第2期36-38,共3页
通常情况下,RTK手薄使用的2000国家大地坐标系和1980西安坐标系,二者间的转换参数为4参数,适用控制区域面积小,一般不能超过20 km×20 km,不利于RTK大区域作业。为满足基于河南省连续卫星运行参考站(He NCORS)的RTK大区域作业需求,... 通常情况下,RTK手薄使用的2000国家大地坐标系和1980西安坐标系,二者间的转换参数为4参数,适用控制区域面积小,一般不能超过20 km×20 km,不利于RTK大区域作业。为满足基于河南省连续卫星运行参考站(He NCORS)的RTK大区域作业需求,文章对适用于河南省行政区域的Bursa 7参数求取方法和实际应用等技术进行了研究。通过实践验证,得出一组适用全省的2000国家大地坐标系与1980西安坐标系的Bursa 7转换参数,并以Trimble TSC2手薄为例介绍其使用方法。 展开更多
关键词 坐标系 TRK GPS bursa 7参数
下载PDF
Trochanteric area pain,the result of a quartet of bursal inflammation
17
作者 Bruce Rothschild 《World Journal of Orthopedics》 2013年第3期100-102,共3页
Bursitis is quite responsive to therapeutic intervention, once the afflicted area is accurately identified. This is especially notable for some hip complaints. Patients' use of the term "hip" can relate ... Bursitis is quite responsive to therapeutic intervention, once the afflicted area is accurately identified. This is especially notable for some hip complaints. Patients' use of the term "hip" can relate to anything from the low back to groin to lateral thigh pain. Trochanteric area surface localization of "hip" pain may afford an opportunity for immediate cure. Effectiveness of therapeutic intervention is predicated upon injection of not one or two, but all four peri-trochanteric bursa with a depot(minimally water-soluble) corticosteroid. The term trochanteric bursitis suggests that the inflammation is more focal than what is clinically observed. While easier to express, perhaps it is time to refer to inflammation in this area, naming all four affected bursae. 展开更多
关键词 Trochanter BURSITIS bursa Hip Injection CORTICOSTEROIDS DEXAMETHASONE TRIAMCINOLONE
下载PDF
面向线路空间多源地理实景配准的改进Bursa算法
18
作者 侯维捷 丁志广 +3 位作者 梁祖鸿 叶智杰 张晓光 文习鹤 《测绘通报》 CSCD 北大核心 2021年第S01期70-74,共5页
反映线路空间状态的多源实景配准融合精度一直制约着实景仿真技术的纵深使用。针对该问题,本文提出在不重组重构数据的前提下,以"三维设计模型作为理论真值、激光三维点云提供线路精确几何特征、无人机倾斜摄影真三维作为线路周边... 反映线路空间状态的多源实景配准融合精度一直制约着实景仿真技术的纵深使用。针对该问题,本文提出在不重组重构数据的前提下,以"三维设计模型作为理论真值、激光三维点云提供线路精确几何特征、无人机倾斜摄影真三维作为线路周边情境"的分工,研究改进Bursa算法以提升既有实景配准精度。实例表明,改进的Bursa算法对坐标系配准精度提升了10%~50%,算法本身对配准精度的损失可忽略,多源实景叠加点位差均值为1.85 cm,小于2.5 cm的要求。该配准算法简单,便于实现,配准后实景空间属性完整、效果逼真,满足线路空间仿真测量需求。 展开更多
关键词 输电线路 空间仿真 地理实景 配准 bursa算法
下载PDF
荠菜(Capsella bursa-pastoris(L.) Medic)种子萌发特性 被引量:8
19
作者 亚吉东 李树珍 +3 位作者 申仕康 申意 王跃华 蒋连计 《种子》 CSCD 北大核心 2009年第1期37-39,43,共4页
通过不同温度和外源激素处理,对荠菜种子萌发特性进行了研究。结果表明:15℃的萌发条件可以在一定程度上解除荠菜种子的休眠,提高种子萌发率;外源激素GA处理能解除种子休眠和提高其萌发率,6-BA和IAA对种子的处理效果远不及GA的处理,高浓... 通过不同温度和外源激素处理,对荠菜种子萌发特性进行了研究。结果表明:15℃的萌发条件可以在一定程度上解除荠菜种子的休眠,提高种子萌发率;外源激素GA处理能解除种子休眠和提高其萌发率,6-BA和IAA对种子的处理效果远不及GA的处理,高浓度(>50 mg/L)和长时间(36 h)的IAA处理甚至具有一定的抑制作用,综合分析认为,200 mg/L的GA浸种36 h为荠菜种子萌发的最佳激素处理方式。 展开更多
关键词 荠菜 种子 激素 萌发率
下载PDF
The Application of the Bursa Model to the Integration of GPS Time Series
20
作者 Wang Ziyan Lin Shu +2 位作者 Wu Yanqiang Zhan Wei Ding Xiaoguang 《Earthquake Research in China》 2014年第1期46-53,共8页
In this paper the method of combining the Bursa model to integrate several regional time series to derive a unified global time series is introduced in detail. Then,an example taken from CMONOC( Crustal Movement Obser... In this paper the method of combining the Bursa model to integrate several regional time series to derive a unified global time series is introduced in detail. Then,an example taken from CMONOC( Crustal Movement Observation Network of China) is used to test if the combination method is feasible. The precision of the integrated time series with the combination method is below 2mm( North),3mm( East),that is same as the results from the direct integration of the time series and the precision of the baseline is below 6mm,which proves that the combination method can be used to integrate several regional time series to derive a unified global time series. 展开更多
关键词 GPS time series INTEGRATION bursa model
下载PDF
上一页 1 2 32 下一页 到第
使用帮助 返回顶部