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Non-Zero Degree Maps Between 2n-Manifolds 被引量:1
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作者 HaiBaoDUAN 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2004年第1期1-14,共14页
Thom–Pontrjagin constructions are used to give a computable necessary and sufficient condition for a homomorphism ? : H n (L;Z) → H n (M;Z) to be realized by a map f : M → L of degree k for closed (n ? 1)-connected... Thom–Pontrjagin constructions are used to give a computable necessary and sufficient condition for a homomorphism ? : H n (L;Z) → H n (M;Z) to be realized by a map f : M → L of degree k for closed (n ? 1)-connected 2n-manifolds M and L, n > 1. A corollary is that each (n ? 1)-connected 2n-manifold admits selfmaps of degree larger than 1, n > 1. In the most interesting case of dimension 4, with the additional surgery arguments we give a necessary and sufficient condition for the existence of a degree k map from a closed orientable 4-manifold M to a closed simply connected 4-manifold L in terms of their intersection forms; in particular, there is a map f : M → L of degree 1 if and only if the intersection form of L is isomorphic to a direct summand of that of M. 展开更多
关键词 2n-manifolds non-zero degree maps
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Formula for calculating spatial similarity degrees between point clouds on multi-scale maps taking map scale change as the only independent variable 被引量:6
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作者 Yang Weifang Yan Haowen Li Jonathan 《Geodesy and Geodynamics》 2015年第2期113-125,共13页
The degree of spatial similarity plays an important role in map generalization, yet there has been no quantitative research into it. To fill this gap, this study first defines map scale change and spatial similarity d... The degree of spatial similarity plays an important role in map generalization, yet there has been no quantitative research into it. To fill this gap, this study first defines map scale change and spatial similarity degree/relation in multi-scale map spaces and then proposes a model for calculating the degree of spatial similarity between a point cloud at one scale and its gener- alized counterpart at another scale. After validation, the new model features 16 points with map scale change as the x coordinate and the degree of spatial similarity as the y coordinate. Finally, using an application for curve fitting, the model achieves an empirical formula that can calculate the degree of spatial similarity using map scale change as the sole independent variable, and vice versa. This formula can be used to automate algorithms for point feature generalization and to determine when to terminate them during the generalization. 展开更多
关键词 Spatial similarity degree map generalization map scale change Point clouds Quantitative description Spatial similarity relations Multi-scale map spaces Curve fitting method
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ON THE DEGREE THEORY FOR MULTIVALUED(S_+) TYPE MAPPINGS 被引量:1
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作者 刘振海 张石生 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1998年第12期0-0,0-0+0-0+0-0+0,共9页
关键词 AM UC CR ON THE degree THEORY FOR MULTIVALUED TYPE mapPINGS SI
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DEGREE THEORY FOR MULTIVALUED (S) TYPE MAPPINGS AND FIXED POINT THEOREMS
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作者 张石生 陈玉清 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1990年第5期441-454,共14页
The main purpose of this paper is devoted to generalizing the results of Browder[1,2]This paper consists of four parts. In the first part, we introduce the concepts of multivalued (S) and (S), type mappings and the co... The main purpose of this paper is devoted to generalizing the results of Browder[1,2]This paper consists of four parts. In the first part, we introduce the concepts of multivalued (S) and (S), type mappings and the concepts of the limits of multivalued (S) and (S) + type mappings. These kinds of mappings contain many monotone type mappings, such as maximal monotone mapping, bounded pseudo-monotone mapping and bounded generalized pseudo-monotone mapping, as its special cases. In the second part we define the pseudo-degree for (S) type mapping and the degree for (S)+ type mapping. These two kinds of degrees are all the generalizations of the degree defined by Browder[1,2] As applications, we utilize the degree theory presented in part 2 to study the existence of solutions for the multivalued operator equations (see part 3) and to obtain some new fixed point theorems in part 4. 展开更多
关键词 TYPE mapPINGS AND FIXED POINT THEOREMS degree THEORY FOR MULTIVALUED
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Comparison of detection results of hypoxic-ischemic encephalopathy at different degrees in infant patients between brain electrical activity mapping, transcranial Doppler sonography and computer tomography examinations
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作者 Dongruo He Xiaoying Xu +1 位作者 Yinghui Zhang Guochao Han 《Neural Regeneration Research》 SCIE CAS CSCD 2006年第4期379-381,共3页
BACKGROUND: It has been proved that brain electrical activity mapping (BEAM) and transcranial Doppler (TCD) detection can reflect the function of brain cell and its diseased degree of infant patients with moderat... BACKGROUND: It has been proved that brain electrical activity mapping (BEAM) and transcranial Doppler (TCD) detection can reflect the function of brain cell and its diseased degree of infant patients with moderate to severe hypoxic-ischemic encephalopathy (HIE). OBJECTIVE: To observe the abnormal results of HIE at different degrees detected with BEAM and TCD in infant patients, and compare the detection results at the same time point between BEAM, TCD and computer tomography (CT) examinations. DESIGN : Contrast observation SETTING: Departments of Neuro-electrophysiology and Pediatrics, Second Affiliated Hospital of Qiqihar Medical College. PARTICIPANTS: Totally 416 infant patients with HIE who received treatment in the Department of Newborn Infants, Second Affiliated Hospital of Qiqihar Medical College during January 2001 and December 2005. The infant patients, 278 male and 138 female, were at embryonic 37 to 42 weeks and weighing 2.0 to 4.1 kg, and they were diagnosed with CT and met the diagnostic criteria of HIE of newborn infants compiled by Department of Neonatology, Pediatric Academy, Chinese Medical Association. According to diagnostic criteria, 130 patients were mild abnormal, 196 moderate abnormal and 90 severe abnormal. The relatives of all the infant patients were informed of the experiment. METHOOS: BEAM and TCD examinations were performed in the involved 416 infant patients with HIE at different degrees with DYD2000 16-channel BEAM instrument and EME-2000 ultrasonograph before preliminary diagnosis treatment (within 1 month after birth) and 1,3,6,12 and 24 months after birth, and detected results were compared between BEAM, TCD and CT examinations. MAIN OUTCOME MEASURES: Comparison of detection results of HIE at different time points in infant patients between BEAM. TCD and CT examinations. RESULTS: All the 416 infant patients with HIE participated in the result analysis. (1) Comparison of the detected results in infant patients with mild HIE at different time points after birth between BEAM, TCD and CT examinations: BEAM examination showed that the recovery was delayed, and the abnormal rate of BEAM examination was significantly higher than that of CT examination 1 and 3 months after birth [55.4%(72/130)vs. 17.0% (22/130 ),x^2=41.66 ;29.2% ( 38/130 ) vs. 6.2% ( 8/130 ), x^2=23.77, P 〈 0.01 ], exceptional patients had mild abnormality and reached the normal level in about 6 months. TCD examination showed that the disease condition significantly improved and infant patients with HIE basically recovered 1 or 2 months after birth, while CT examination showed that infant patients recovered 3 or 4 months after birth. (2) Comparison of detection results of infant patients with moderate HIE at different time points between BEAM, TCD and CT examinations: The abnormal rate of BEAM examination was significantly higher than that of CT examination 1,3,6 and 12 months after birth [90.8% (178/196),78.6% (154/196),x^2=4.32,P 〈 0.05;64.3% (126/196),43.9% (86/196) ,x^2=16.44 ;44.9% (88/196) ,22.4% (44/196),x^2=22.11 ;21.4% (42/196), 10.2% (20/196),x^2=9.27, P 〈 0.01]. BEAM examination showed that there was still one patient who did not completely recovered in the 24^th month due to the relatives of infant patients did not combine the treatment,. TCD examination showed that the abnormal rate was 23.1%(30/196)in the 1^st month after birth, and all the patients recovered to the normal in the 3^rd month after birth, while CT examination showed that mild abnormality still existed in the 24^th month after birth (1.0% ,2/196). (3) Comparison of detection results of infant patients with severe HIE at different time points between BEAM, TCD and CT examinations: The abnormal rate of BEAM examination was significantly higher than that of CT examination in the 1^st, 3^rd, 6^th and 12^th months after birth[86.7% (78/90),44.4% (40/90),x^2=35.53;62.2% (56/90),31.1% (28/90),x^2=17.51 ;37.8% (34/90),6.7% (6/90), x^2=27.14, P 〈 0.01]. BEAM examination showed that mild abnormality still existed in 4 infant patients in the 24^th month after birth. TCD examination showed that the abnormal rate was 11.1% (10/90) in the 3^rd month after birth, and all the infant patients recovered in the 6^th month after birth. CT examination showed that the abnormal rate was 6.7%(6/90) in the 12^th month after birth, and all of infant patients recovered to the normal in the 24^th month after birth.CONCLUSION : BEAM is the direct index to detect brain function of infant patients with HIE, and positive reaction is still very sensitive in the tracking detection of convalescent period. The positive rate of morphological reaction in CT examination is superior to that in TCD examination, and the positive rate is very high in the acute period of HIE in examination. 展开更多
关键词 HIE Comparison of detection results of hypoxic-ischemic encephalopathy at different degrees in infant patients between brain electrical activity mapping transcranial Doppler sonography and computer tomography examinations
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Gd-EOB-DTPA增强MRI T_(1) mapping鉴别不同分化程度肝细胞癌的价值 被引量:15
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作者 成戈 董妍 +1 位作者 余雪燕 周智鹏 《临床放射学杂志》 北大核心 2021年第4期717-722,共6页
目的探讨钆塞酸二钠(Gd-EOB-DTPA)增强MRI T_(1)mapping技术对不同分化程度肝细胞癌(HCC)的鉴别诊断价值。方法搜集2017年7月至2020年5月桂林医学院附属医院经手术病理证实为HCC患者48例共50个病灶,所有患者术前1个月内均进行过Gd-EOB-D... 目的探讨钆塞酸二钠(Gd-EOB-DTPA)增强MRI T_(1)mapping技术对不同分化程度肝细胞癌(HCC)的鉴别诊断价值。方法搜集2017年7月至2020年5月桂林医学院附属医院经手术病理证实为HCC患者48例共50个病灶,所有患者术前1个月内均进行过Gd-EOB-DTPA增强MRI扫描,采用可变多翻转角T_(1)mapping成像技术,获得增强前、增强后20 min的T_(1)mapping图像。分别测量增强前及增强后20 min的T_(1)弛豫时间T_(1pre)、T_(1post) ,并计算T_(1)弛豫时间减低率(ΔT_(1)%)。根据病理结果,将患者分为3组,高分化HCC 16个,中分化HCC 27个,低分化HCC 7个。采用单因素方差分析比较不同组之间T_(1pre)、T_(1post) 、ΔT_(1)%的差异。采用Spearman等级相关分析评价T_(1pre)、T_(1post) 、ΔT_(1)%与不同分化程度HCC的相关性。采用受试者工作特征曲线(ROC)评估T_(1pre)、T_(1post) 、ΔT_(1)%对不同分化程度HCC的鉴别诊断效能。结果 3组不同分化程度HCC间的T_(1post) 、ΔT_(1)%差异具有统计学意义(P<0.05),T_(1pre)差异无统计学意义(P>0.05)。T_(1post) 和ΔT_(1)%对于鉴别高分化与中分化、高分化与低分化、低分化与中分化HCC的ROC曲线下面积分别为0.752、0.911、0.709,0.775、0.973、0.857;T_(1post) 与HCC的分化程度呈负相关(r值为-0.512,P<0.05),ΔT_(1)%与HCC的分化程度呈正相关(r值为0.614,P<0.05)。ΔT_(1)%的诊断效能更高。结论 Gd-EOB-DTPA增强MRI T_(1)mapping成像对不同分化程度HCC具有鉴别诊断价值,可以作为术前预测HCC病理分级的一种较为可靠的无创检查手段。 展开更多
关键词 钆塞酸二钠 T1mapping成像 肝细胞癌 分化程度
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预估计混叠度的MAP超分辨率处理算法 被引量:22
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作者 孟庆武 《软件学报》 EI CSCD 北大核心 2004年第2期207-214,共8页
提出一种预估计混叠度的PEMAP(pre-estimated MAP (maximum a posteriori))算法,用于卫星图像的地面超分辨率处理.它通过频域分析确定卫星图像的混叠度,将其作为先验信息在空域控制MAP估计的循环迭代,联合估计帧间位移和高分辨率图像.... 提出一种预估计混叠度的PEMAP(pre-estimated MAP (maximum a posteriori))算法,用于卫星图像的地面超分辨率处理.它通过频域分析确定卫星图像的混叠度,将其作为先验信息在空域控制MAP估计的循环迭代,联合估计帧间位移和高分辨率图像.该算法克服了最大后验概率MAP算法的盲目性和不稳定性,使其适应性更好.实际的卫星图像处理显示了较好的处理效果. 展开更多
关键词 卫星图像 超分辨率处理 混叠度 位移参数 map(maximum a postenori)估计
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联合估计混叠度,运动参数和高分辨率图像的JEMAP算法 被引量:2
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作者 孟庆武 孟新 《计算机科学》 CSCD 北大核心 2004年第6期184-188,共5页
本文提出一种空域联合估计混叠度,运动参数和高分辨率图像的JEMAP算法,以提高超分辨平处理的适应性,在地面上稳定地获得高于实测卫星图像中所用CCD设备成像精度的高清晰图像。算法根据星载CCD设备的成像机理,定义卫星图像的混叠度,确定... 本文提出一种空域联合估计混叠度,运动参数和高分辨率图像的JEMAP算法,以提高超分辨平处理的适应性,在地面上稳定地获得高于实测卫星图像中所用CCD设备成像精度的高清晰图像。算法根据星载CCD设备的成像机理,定义卫星图像的混叠度,确定超分辨率处理模型,通过空域迭代联合估计混叠度,运动参数和高分辨率图像。实际卫星图像处理表明JEMAP算法具有很好的适应性和穗定性,包含先验约束能力较强,可以解开欠采样低分辨率输入图像的混叠,重构清晰卫星图像。 展开更多
关键词 成像模型 混叠度 运动参数 高分辨率图象 联合map估计
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基于Z-Map留量模型的补加工研究 被引量:3
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作者 刘建元 刘世能 《制造技术与机床》 CSCD 北大核心 2011年第2期154-157,共4页
补加工是CAM软件编程的关键技术之一,补加工就是适时确定毛坯的残留状态及残留量并据此生成相应刀具的精简高效、科学合理的刀轨。Z-Map留量模型是一种描述留量的几何模型,毛坯加工过程中不断变化的数字模型由大量的Z-Map点构成,Z-Map... 补加工是CAM软件编程的关键技术之一,补加工就是适时确定毛坯的残留状态及残留量并据此生成相应刀具的精简高效、科学合理的刀轨。Z-Map留量模型是一种描述留量的几何模型,毛坯加工过程中不断变化的数字模型由大量的Z-Map点构成,Z-Map留量模型能如实反映毛坯适时的残留状态、可自动识别补加工区域且计算简单,对传统Z-Map留量模型的改进处理可提高加工精度及运算处理速度。基于Z-Map留量模型CAM软件易于实现补加工编程智能化。 展开更多
关键词 Z-map留量模型 补加工 截交线 三角形网格 平坦度系数 二叉树
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思维导图引导康复护理在飞秒激光辅助白内障超声乳化手术患者中的应用效果
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作者 陈诵惟 孙冬云 +2 位作者 黄叶萌 秦秀芝 朱曦 《中外医药研究》 2025年第19期125-127,共3页
目的:探讨思维导图引导康复护理在飞秒激光辅助白内障超声乳化手术患者中的应用效果。方法:选取2023年8—10月于南通大学附属医院行飞秒激光辅助白内障超声乳化手术的白内障患者80例,随机分为对照组与研究组,每组40例。对照组给予常规... 目的:探讨思维导图引导康复护理在飞秒激光辅助白内障超声乳化手术患者中的应用效果。方法:选取2023年8—10月于南通大学附属医院行飞秒激光辅助白内障超声乳化手术的白内障患者80例,随机分为对照组与研究组,每组40例。对照组给予常规护理干预,研究组在对照组基础上行思维导图引导康复护理干预。比较两组焦虑程度、生活质量以及并发症发生情况。结果:术后1周、出院后1个月,研究组焦虑自评量表评分低于对照组(P<0.001);护理后,研究组躯体症状、社会功能、心理状况评分高于对照组(P<0.001);研究组并发症总发生率低于对照组(P=0.043)。结论:思维导图引导康复护理在飞秒激光辅助白内障超声乳化手术患者中的应用效果显著,可缓解患者负面情绪,提高生活质量,降低并发症发生风险。 展开更多
关键词 思维导图 康复护理 飞秒激光 白内障超声乳化手术 焦虑程度 生活质量
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一种面向海洋观测数据的智能处理算法设计
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作者 齐光鹏 《现代电子技术》 北大核心 2025年第8期133-138,共6页
针对海洋的现代化智能观测需求,提出一种基于模糊SVM算法的海洋观测数据智能处理算法。为了解决海洋多维指标数据的线性不可分问题,采用模糊隶属度对训练样本进行模糊映射,并在此基础上利用拉格朗日模糊偏导数方法将最优化问题转化为二... 针对海洋的现代化智能观测需求,提出一种基于模糊SVM算法的海洋观测数据智能处理算法。为了解决海洋多维指标数据的线性不可分问题,采用模糊隶属度对训练样本进行模糊映射,并在此基础上利用拉格朗日模糊偏导数方法将最优化问题转化为二次规划问题,从而求解出最佳决策函数。此外,采用基于样本邻近密度的模糊隶属度函数构造方法,有效降低了异常样本对决策函数训练的影响。仿真结果表明,相比于现有算法,所提算法对海洋观测数据处理的正确率高于95%,且对于多种海洋观测专业指标均具有良好的适用性。 展开更多
关键词 海洋智能观测 模糊SVM算法 模糊隶属度 决策函数 模糊映射 二次规划
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一种能对复杂地形进行精细测量的智能测绘车
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作者 陈剑锋 姜骏康 +2 位作者 李霖 李正才 李婷 《电动工具》 2025年第1期20-22,共3页
为了提高道路测绘作业的效率及准确性,设计了一款无人驾驶的智能测绘车。测绘车采用可伸缩式多轮结构,设计了遥控和自动避障功能实现自动驾驶,更适用于复杂地形。测绘车配备了多种接触式传感器,采集道路坡度和平整度数据,通过数据处理... 为了提高道路测绘作业的效率及准确性,设计了一款无人驾驶的智能测绘车。测绘车采用可伸缩式多轮结构,设计了遥控和自动避障功能实现自动驾驶,更适用于复杂地形。测绘车配备了多种接触式传感器,采集道路坡度和平整度数据,通过数据处理与自动制图功能实现了三维地形绘制。 展开更多
关键词 测绘仪器 全站型电子速测仪 传感器 坡度 平整度
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基于地学信息图谱的桂西南地区土地利用时空变化特征分析
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作者 何金妮 刘霞 +4 位作者 黄秋霞 吴宇华 蒋卓越 项小雨 黄春圆 《中国资源综合利用》 2025年第4期87-92,共6页
以桂西南地区为例,基于地理信息技术分析其土地利用时空变化态势,可为该地区土地资源的合理利用和保护提供依据。基于2000-2020年土地利用数据,应用地理信息系统(Geographic Information System,GIS)技术,利用土地利用动态度、转移图谱... 以桂西南地区为例,基于地理信息技术分析其土地利用时空变化态势,可为该地区土地资源的合理利用和保护提供依据。基于2000-2020年土地利用数据,应用地理信息系统(Geographic Information System,GIS)技术,利用土地利用动态度、转移图谱、涨落图谱,分析桂西南地区2000-2020年土地利用时空演变特征。桂西南地区土地利用类型以林地为主,林地面积占55%以上,耕地次之。自2000年以来,桂西南地区林地面积逐步减小,建设用地与水域面积逐步扩大,草地和耕地用地动态度有时间变化差异,但耕地面积变动频率较小。在土地利用变化模式图谱中,用地面积最大为稳定型图谱单元,前期变化型图谱占比面积最小。在涨落式图谱分析中,2000-2010年,耕地扩张面积最大(39.4%),林地面积减少最大(51.4%);2010-2020年,扩张林地面积最大(37%);2010-2020年,林地面积减少的速度虽缓慢,但仍然占比最大,占变化总面积的43.16%。 展开更多
关键词 土地利用 地学信息图谱 土地利用动态度 桂西南地区
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互联网联合思维导图健康教育在卵巢癌术后患者中的应用观察
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作者 马丽玥 师文 +1 位作者 冀润芳 甘雪梅 《中国计划生育学杂志》 2025年第7期1581-1587,共7页
目的:探究互联网联合思维导图健康教育在卵巢癌术后患者中应用效果。方法:随机数字表法将2021年5月-2023年5月本院治疗的92例卵巢癌术后患者分为两组各46例,均予以常规护理干预,观察组同时给予互联网联合思维导图健康教育。比较干预前... 目的:探究互联网联合思维导图健康教育在卵巢癌术后患者中应用效果。方法:随机数字表法将2021年5月-2023年5月本院治疗的92例卵巢癌术后患者分为两组各46例,均予以常规护理干预,观察组同时给予互联网联合思维导图健康教育。比较干预前后两组自我管理能力[自我护理能力测定量表(ESCA)评分]、疲乏程度[癌因性疲乏量表(CFS)评分]、生活质量[生活质量测定量表(EORTC QLQ-C30)评分],统计两组患者治疗依从性及术后恢复情况。结果:干预后观察组CFS量表各维度评分均低于对照组,ESCA及EORTC QLQ-C30量表各维度评分高于对照组,术后首次下床活动时间(36.58±7.22h)、首次排便时间(45.73±10.13h)及住院时间(9.04±3.27d)均短于对照组(49.84±10.29h、59.18±12.37h、11.98±3.55d),治疗依从性(95.7%)高于对照组(80.4%),不良反应发生率(8.7%)低于对照组(23.9%)(均P<0.05)。结论:卵巢癌术后实施互联网联合思维导图健康教育可促进患者早期康复,提高治疗依从性,减轻疲乏程度,增强自我管理能力,降低不良反应发生率,利于改善生活质量。 展开更多
关键词 卵巢癌术后 健康教育 互联网 思维导图 依从性 疲乏程度 自我管理
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MODIFIED ROPER-SUFFRIDGE OPERATOR FOR SOME SUBCLASSES OF STARLIKE MAPPINGS ON REINHARDT DOMAINS 被引量:10
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作者 王建飞 《Acta Mathematica Scientia》 SCIE CSCD 2013年第6期1627-1638,共12页
In this note, the author introduces some new subcIasses of starlike mappings S^*Ωn1p2,…,pn(β,A,B)={f∈H(Ω):|itanβ+(1-itanβ)2/p(z)аp/аz(z)Jf^-1(z)f(z)-1-AB/1-B^2|〈B-A/1-B^2},on Reinhardt dom... In this note, the author introduces some new subcIasses of starlike mappings S^*Ωn1p2,…,pn(β,A,B)={f∈H(Ω):|itanβ+(1-itanβ)2/p(z)аp/аz(z)Jf^-1(z)f(z)-1-AB/1-B^2|〈B-A/1-B^2},on Reinhardt domains Ωn1p2,…,pn=z∈C^n:|z1|^2+n∑j=2|zj|^pj〈1}where - 1≤A〈B〈1,q=min{p2,…,pn}≥1,l=max{p2,…,pn}≥2 and β ∈(-π/2,π/2).Some different conditions for P are established such that these classes are preserved under the following modified Roper-Suffridge operator F(z)=(f(z1)+f'(z1)Pm(z0),(f'(z1))^1/mz0)'where f is a normalized biholomorphic function on the unit disc D, z = (z1,z0) ∈Ωn1p2,…,pn,z0=(z2,…,zn)∈ C^n-1.Another condition for P is also obtained such that the above generalized Roper-Suffridge operator preserves an almost spirallike function of type/3 and order β These results generalize the modified Roper-Suffridge extension oper-ator from the unit ball to Reinhardt domains. Notice that when p2 = p3 …=pn = 2,our results reduce to the recent results of Feng and Yu. 展开更多
关键词 biholomorphic mappings Roper-Suffridge extension operator Reinhardt do-mains Starlike mappings homogeneous polynomial of degree m
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Classification of rational holomorphic maps from B^2 into B^N with degree 2 被引量:5
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作者 JI ShanYu 1 & ZHANG Yuan 2 1 Department of Mathematics, University of Houston, Houston, TX 77204, USA 2 Department of Mathematics, University of California at San Diego, La Jolla, CA 92093, USA 《Science China Mathematics》 SCIE 2009年第12期2647-2667,共21页
Rational proper holomorphic maps from the unit ball in C 2 into the unit ball C N with degree 2 are classified, up to automorphisms of balls.
关键词 RATIONAL HOLOMORPHIC maps between BALLS CLASSIFICATION maps with degree 2
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MRI T2-mapping检查在颈椎间盘退行性变程度评估中的应用价值研究 被引量:10
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作者 王仓义 李月河 +2 位作者 钱冬乐 程军 贾春岩 《临床误诊误治》 CAS 2022年第5期65-68,共4页
目的探讨MRI T2-mapping检查在颈椎间盘退行性变程度评估中的价值。方法选取2020年2月—2021年5月我院53例受检者行常规颈椎MRI及T2-mapping扫描,行颈椎间盘Pfirrmann分级及髓核T2值测定,分析髓核T2值与Pfirrmann分级的相关性,绘制受试... 目的探讨MRI T2-mapping检查在颈椎间盘退行性变程度评估中的价值。方法选取2020年2月—2021年5月我院53例受检者行常规颈椎MRI及T2-mapping扫描,行颈椎间盘Pfirrmann分级及髓核T2值测定,分析髓核T2值与Pfirrmann分级的相关性,绘制受试者工作特征(ROC)曲线分析髓核T2值对Pfirrmann分级的诊断准确度,同时比较不同年龄段、颈椎间盘节段髓核T2值。结果53例受检者共265个颈椎间盘,MRI髓核T2值随Pfirrmann分级升高而逐渐降低(P<0.01);不同Pfirrmann分级受检者MRI髓核T2值存在明显差异(P<0.05)。Spearman相关性分析显示,髓核T2值与Pfirrmann分级呈负相关(r=-0.673,P<0.01)。ROC曲线显示,髓核T2值诊断Ⅰ级和Ⅱ级、Ⅱ级和Ⅲ级、Ⅲ级和Ⅳ级颈椎间盘退行性变的准确度中等,曲线下面积分别为0.739、0.817及0.784。22~30岁受检者中,不同颈椎间盘节段MRI髓核T2值存在明显差异(P<0.01);31~45岁受检者不同颈椎间盘节段MRI髓核T2值明显小于22~30岁受检者(P<0.01)。结论MRI T2-mapping检查可用于颈椎间盘退行性变程度的评估,髓核T2值具有定量检测颈椎间盘退行性变程度的潜能,在疗效评估、病情监测等方面起重要作用。 展开更多
关键词 椎间盘退行性变 颈椎病 磁共振成像 T2-mapping检查 病变程度 诊断价值
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Compilation of hydrogeological map of China 被引量:1
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作者 ZHANG Jian-kang DONG Hua +2 位作者 CHENG Yan-pei YUE Chen LIU Kun 《Journal of Groundwater Science and Engineering》 2020年第4期381-395,共15页
Hydrogeological map is one of the important carriers of groundwater related information.It directly reflects the hydrogeological conditions and previous investigation and research results of a mapping area.The hydroge... Hydrogeological map is one of the important carriers of groundwater related information.It directly reflects the hydrogeological conditions and previous investigation and research results of a mapping area.The hydrogeological map of China is a map reflecting the characteristics of hydrogeology and groundwater dynamics on a national scale.On the basis of the hydrogeological map of China(1:4000000)compiled in 1988,this map compilation attempted to update and enhance the existing map,with the latest survey results from the project of National Investigation and Evaluation of Groundwater Resources and Environmental Problems led by China Geological Survey.Task of the mapping program included redefining groundwater types,quantifying the classification standard of the groundwater and adding the pore-fissure water in laterite layer of hilly basin.The multilayer structures for porous,karst and porous-fractured groundwater and their water-rich grades are reflected on the map.Based on the comprehensive summary of the latest hydrogeological data of China,this research conducts an in-depth analysis of the regional distribution characteristics of groundwater in China,utilizes a digital mapping process and establishes a cartographic database for the purpose of further use.With the enrichment of the content and the continuous improvement of cognitive level,mapping content can be updated quickly,which has practical significance for the concept of surveying and mapping and scientific popularization. 展开更多
关键词 Hydrogeology map mapping methods Groundwater types Water-bearing degree Groundwater regional distribution characteristics
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Brouwer degrees of gradient maps of isoparametric functions
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作者 彭家贵 唐梓洲 《Science China Mathematics》 SCIE 1996年第11期1131-1139,共9页
The Brouwer degree of every isoparametric gradient map has been given by using moving frame. It has been used to construct the harmonic representations of the elements of homotopy groups of the spheres.
关键词 Brouwer degree isoparametric map HARMONIC map.
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Brouwer degrees of the gradient maps of isoparametric functions
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作者 郭瑞芝 《Chinese Science Bulletin》 SCIE EI CAS 1996年第21期1770-1775,共6页
Let M,N be oriented closed manifolds of dimension n.Denote the Brouwer degree ofa smooth map g: M→N by deg(g).It is well known that deg(g)=sum from x∈g<sup>-1</sup>(y) sign dg<sub>x</sub&g... Let M,N be oriented closed manifolds of dimension n.Denote the Brouwer degree ofa smooth map g: M→N by deg(g).It is well known that deg(g)=sum from x∈g<sup>-1</sup>(y) sign dg<sub>x</sub>,where yis a regular value of g.When M=N=S<sup>n+1</sup>,the homotopy class [g]∈multiply from n+1 S<sup>n+1</sup>≌Z is deter-mined by the Brouwer degree of g.Since finding a harmonic representative of an elementin multiply from n+1 S<sub>n+1</sub> is important(see refs.[1—3]),it is necessary to calculate the Brouwer degree ofa map. 展开更多
关键词 isoparametric POLYNOMIAL Brouwer degree HARMONIC map.
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