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Multi-scale Approaches toward Sustainable Development 被引量:1
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作者 毕晓涛 金涌 《过程工程学报》 CAS CSCD 北大核心 2005年第4期464-472,共9页
Approaches toward the sustainable development need integrated considerations of technical, economical, environmental/ecological and social issues. Current approaches from different disciplines can be grouped into at l... Approaches toward the sustainable development need integrated considerations of technical, economical, environmental/ecological and social issues. Current approaches from different disciplines can be grouped into at least three levels: micro-scale, meso-scale and macro-scale. At the micro-scale, green chemistry carries out chemical activities such as chemical design and synthesis so that environmentally benign chemicals can be synthesized without using and generating hazardous substances. Green engineering, at the meso-scale, develops green industrial processes or clean technologies via pollution prevention and cleaner production, which will cause minimal damages or dangers to the environment and ecosystems when the product is manufactured and used. Industrial ecology at the industrial complex or community level seeks to optimize energy and materials use and minimize waste generation in industrial systems or communities by promoting planned materials and energy exchanges. Incorporation of ecological principles with the life cycle thinking in the chemical pathway synthesis, product design, process development, and industrial system and community planning appears to be the most promising engineering approach in achieving sustainable industrial development. 展开更多
关键词 多尺度方法 可持续发展 污染防治 清洁生产工艺 复合系统 发展经济学
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基于多尺度Scale-Unet的单样本图像翻译
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作者 周蓬勃 冯龙 寇宇帆 《计算机技术与发展》 2024年第4期55-61,共7页
随着生成对抗网络(GAN)的发展,基于单样本的无监督图像到图像翻译(UI2I)取得了重大进展。然而,以前方法无法捕获图像中的复杂纹理并保留原始内容信息。为解决这个问题,提出了一种基于尺度可变U-Net结构(Scale—Unet)的新型单样本图像翻... 随着生成对抗网络(GAN)的发展,基于单样本的无监督图像到图像翻译(UI2I)取得了重大进展。然而,以前方法无法捕获图像中的复杂纹理并保留原始内容信息。为解决这个问题,提出了一种基于尺度可变U-Net结构(Scale—Unet)的新型单样本图像翻译结构SUGAN。所提出的SUGAN使用Scale—Unet作为生成器,利用多尺度结构和渐进方法不断改进网络结构,以从粗到细地学习图像特征。同时,提出了尺度像素损失scale-pixel来更好地约束保留原始内容信息,防止信息丢失。实验表明,与SinGAN、TuiGAN、TSIT、StyTR2等公共数据集Summer■Winter、Horse■Zebra上的方法相比,该方法生成图像的SIFID值平均降低了30%。所提方法可更好地保留图像内容信息,同时生成详细逼真的高质量图像。 展开更多
关键词 单样本图像翻译 scale-Unet 多尺度结构 渐进方法 尺度像素损失
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Settlement characteristics of bridge approach embankment based on scale model test 被引量:3
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作者 ZHANG Jiu-peng LIU Tao +3 位作者 PEI Jian-zhong LI Rui ZOU Dao-guang ZHANG Yu-qing 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第7期1956-1964,共9页
In order to analyze the effects of backfill materials, geometries and slab setting on the settlement of bridge approach embankment, scale model was built based on the structural characteristics of bridge approach emba... In order to analyze the effects of backfill materials, geometries and slab setting on the settlement of bridge approach embankment, scale model was built based on the structural characteristics of bridge approach embankment, and scale model tests were carried out under different conditions. The results show that when graded gravels were selected as the backfill materials, the effect of setting approach slab to reduce the differential settlement is more prominent. When lime soils were selected as the backfill material, approach slab can moderate the longitudinal settlement slope. When using different backfill materials, the ultimate settlement of the positive trapezoidal backfill geometries is less than that of the inverted trapezoid, and the backfill geometries have little effect on the settlement slope. 展开更多
关键词 bridge approach EMBANKMENT scale model SETTLEMENT BACKFILL
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Accelerated Primal-Dual Projection Neurodynamic Approach With Time Scaling for Linear and Set Constrained Convex Optimization Problems
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作者 You Zhao Xing He +1 位作者 Mingliang Zhou Tingwen Huang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第6期1485-1498,共14页
The Nesterov accelerated dynamical approach serves as an essential tool for addressing convex optimization problems with accelerated convergence rates.Most previous studies in this field have primarily concentrated on... The Nesterov accelerated dynamical approach serves as an essential tool for addressing convex optimization problems with accelerated convergence rates.Most previous studies in this field have primarily concentrated on unconstrained smooth con-vex optimization problems.In this paper,on the basis of primal-dual dynamical approach,Nesterov accelerated dynamical approach,projection operator and directional gradient,we present two accelerated primal-dual projection neurodynamic approaches with time scaling to address convex optimization problems with smooth and nonsmooth objective functions subject to linear and set constraints,which consist of a second-order ODE(ordinary differential equation)or differential conclusion system for the primal variables and a first-order ODE for the dual vari-ables.By satisfying specific conditions for time scaling,we demonstrate that the proposed approaches have a faster conver-gence rate.This only requires assuming convexity of the objective function.We validate the effectiveness of our proposed two accel-erated primal-dual projection neurodynamic approaches through numerical experiments. 展开更多
关键词 Accelerated projection neurodynamic approach lin-ear and set constraints projection operators smooth and nonsmooth convex optimization time scaling.
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Microanalysis of Multi-Element in Juncus effusus L. by LIBS Technique 被引量:2
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作者 刘晓娜 黄建梅 +5 位作者 吴志生 张乔 史新元 赵娜 贾帅芸 乔延江 《Plasma Science and Technology》 SCIE EI CAS CSCD 2015年第11期904-908,共5页
Laser-induced breakdown spectroscopy (LIBS) was used to decipher the unique multi-elemental characteristics of Juncus effusus L. The spectral fingerprints of Juncus effusus L. were established based on elemental mic... Laser-induced breakdown spectroscopy (LIBS) was used to decipher the unique multi-elemental characteristics of Juncus effusus L. The spectral fingerprints of Juncus effusus L. were established based on elemental microanalysis via LIBS. Microanalysis and multimode sampling methodologies were designed in this study. The relative standard deviation (RSD) approach was performed to optimize the multi-shot measurements. Taking advantage of the capability with no or minimal sample pre-treatment of LIBS, a thermodynamic chart of four elements (Mg, Ca, Ba, and Na) was created from twelve collection regions. The diagram of elemental distribution on a micro-scale was generated to explore the nature of Juncus effusus L. by LIBS. The results demon- strated that LIBS is a promising technique for rapid elemental microanalysis of heterogeneous samples. 展开更多
关键词 LIBS Juncus effusus L. RSD approach thermodynamic chart elemental microanalysis MICRO-scale
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An integrated approach to scaling issues in environmental change study
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作者 LIU Hong-hui, YANG Xiao-huan, WANG Nai-bin, LIU Hai-yan (Center for Resources and Environmental Data, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China) 《Journal of Geographical Sciences》 SCIE CSCD 2000年第4期45-52,共8页
Global change research and sustainable development need to be addressed at larger scales in the light of small scale process studies. Much remains to be done before the small scale, process level understanding of ecos... Global change research and sustainable development need to be addressed at larger scales in the light of small scale process studies. Much remains to be done before the small scale, process level understanding of ecosystem responses to global change can be reliably translated to larger scales. The paper reviews the status of scaling issues and tries to find how to extrapolate our observations and our findings at site scale up to regional scale and provide ecological information and interpretations at the regional scale. An integrated approach to scaling-up from site to region is proposed combining hierarchical theory, landscape ecology, remote sensing, geographical information system (GIS) with process/mechanistic modeling. Remote sensing and GIS will play key roles in spatial analysis, integration as well as cross scale modeling. 展开更多
关键词 scale issue global change study scaling up integrated approach
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Second sea-entering approach of Changjiang River: Tongl Canal-planning of control dimensions, analysis of erosion and siltation and selection of outlet
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作者 Lu Wujiang and Jin Jianxin(Research Institute of Coastal and Ocean Engineering, Hobal University, Nangjing 210024, China) 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1995年第1期113-125,共13页
Assume that the Tonglu Canal would be widened and deepened in which a water lock is constructed atthe river side, and made open to the sea side. The canal's planned control dimensions are determined, and the erosi... Assume that the Tonglu Canal would be widened and deepened in which a water lock is constructed atthe river side, and made open to the sea side. The canal's planned control dimensions are determined, and the erosionand siltation characteristics along the river (totally 81. 8 km) are analyzed by the numerical calculation of one-dimen-sional unsteady flow and the relative standards. According to the data of the evolution, hydrology and sediment inthe Xiaomiaohong Waterway, it is found reasonable to select the channel near the Xingang Gate as the second sea-entering approach. This paper is helpful in planning and designing the approach. 展开更多
关键词 Sea-entering approach Tongl■ Canal erosion and siltation analysis planning scale
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Optimal tracking control for nonlinear large-scale systems with persistent disturbances 被引量:1
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作者 Ruichun TANG Xianmin LU +1 位作者 Yili ZHAI Cunqun GONG 《控制理论与应用(英文版)》 EI 2010年第4期515-520,共6页
This paper studies the optimal control with zero steady-state error problem for nonlinear large-scale systems affected by external persistent disturbances.The nonlinear large-scale system is transformed into N nonline... This paper studies the optimal control with zero steady-state error problem for nonlinear large-scale systems affected by external persistent disturbances.The nonlinear large-scale system is transformed into N nonlinear subsystems with interconnect terms.Based on the internal model principle,a disturbance compensator is constructed such that the ith subsystem with external persistent disturbances is transformed into an augmented subsystem without disturbances.According to the sensitivity approach,the optimal tracking control law for the ith nonlinear subsystem can be obtained.The optimal tracking control law for the nonlinear large-scale systems can be obtained.A numerical simulation shows that the method is effective. 展开更多
关键词 Nonlinear systems Large-scale systems Persistent disturbances Optimal tracking control Sensitivity approach
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Optimal tracking control for linear time-delay large-scale systems with persistent disturbances 被引量:1
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作者 Tang Ruichun Ma Huamin +1 位作者 Guo Shuangle Ren Lijie 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第5期1058-1064,共7页
An optimal tracking control (OTC) problem for linear time-delay large-scale systems affected by external persistent disturbances is investigated. Based on the internal model principle, a disturbance compensator is c... An optimal tracking control (OTC) problem for linear time-delay large-scale systems affected by external persistent disturbances is investigated. Based on the internal model principle, a disturbance compensator is constructed. The system with persistent disturbances is transformed into an augmented system without persistent disturbances. The original OTC problem of linear time-delay system is transformed into a sequence of linear two- point boundary value (TPBV) problems by introducing a sensitivity parameter and expanding Maclaurin series around it. By solving an OTC law of the augmented system, the OTC law of the original system is obtained. A numerical simulation is provided to illustrate the effectiveness of the proposed method. 展开更多
关键词 optimal tracking control sensitivity approach time-delay large-scale system persistent disturbance
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Development of a Scale to Evaluate Depressive States among Elderly Patients in General Wards —Verification of the Contents to Improve the Accuracy of the Scale
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作者 Tetsuko Takaoka Ruriko Kidachi 《Open Journal of Nursing》 2021年第6期455-465,共11页
<strong>Purpose:</strong> This study aims to verify the validity of the contents of the Nurse Administered Depression Scale for Elderly Inpatients16 (NDE16) using the Delphi approach in order to further im... <strong>Purpose:</strong> This study aims to verify the validity of the contents of the Nurse Administered Depression Scale for Elderly Inpatients16 (NDE16) using the Delphi approach in order to further improve the accuracy of the NDE16, a scale for rating potential depressive states in elderly inpatients through the observations reported by nurses.<strong> Methods:</strong> Participants were nurses working in general wards for longer than 3 years and who expressed consent to the study participation. Data were collected using the Delphi method (3 times). Responses are scored from 1 to 5 (3 - 5 points as positive) using the Likert method. The standard criteria for inclusion in the further evaluation are “mean ≥ 3.0”, “standard deviation < 1.0”, “median ≥ 3.0”, and “IQR ≤ 1.0”. Items that meet all the criteria at the third survey are employed as question items in the final questionnaire. <strong>Results: </strong>The respondents were 139 females, 10 males, and 1 unknown, aged 25 to 65. The collection rates of the three surveys were 75% to 82%. Based on the results of the first survey, wordings of 9 questions were modified. Since Question 13 “Queries are not really responded to.” did not meet the criteria (IQR = 2) at the third survey, we excluded this question and named the revised scale NDE15. <strong>Discussion: </strong>The reason why Question 13 did not meet the criteria could be due to the difficulty in distinguishing “Expressing thought suppression” from the state of cognitive decline in dementia. Further studies are needed to determine cutoff points. 展开更多
关键词 Depressive States Elderly Patients Delphi approach General Ward Non-Self-Rating scale Nurses
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A Unified Approach to the Thermodynamics and Quantum Scaling Functions of One-Dimensional Strongly Attractive SU(w) Fermi Gases
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作者 余毅聪 管习文 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第7期41-46,共6页
We present a unified derivation of the pressure equation of states, thermodynamics and scaling functions for the one-dimensional (1D) strongly attractive Fermi gases with SU(w) symmetry. These physical quantities ... We present a unified derivation of the pressure equation of states, thermodynamics and scaling functions for the one-dimensional (1D) strongly attractive Fermi gases with SU(w) symmetry. These physical quantities provide a rigorous understanding on a universality class of quantum criticality characterized by the critical exponents z = 2 and correlation length exponent v= 1/2. Such a universality class of quantum criticality can occur when the Fermi sea of one branch of charge bound states starts to fill or becomes gapped at zero temperature. The quantum critical cone can be determined by the double peaks in specific heat, which serve to mark two crossover temperatures fanning out from the critical point. Our method opens to further study on quantum phases and phase transitions in strongly interacting fermions with large SU ( w) and non-SU ( w ) symmetries in one dimension. 展开更多
关键词 A Unified approach to the Thermodynamics and Quantum Scaling Functions of One-Dimensional Strongly Attractive SU
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社区尺度斜入射波场下场地-建筑群耦合作用模拟方法
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作者 巴振宁 付继赛 +2 位作者 王方博 梁建文 牛嘉琪 《振动与冲击》 EI CSCD 北大核心 2024年第4期1-11,37,共12页
场地-城市相互作用(site-city interaction,SCI)效应会显著改变场地地震波场分布及建筑反应,基于SCI效应理论计算研究方法的发展现状,发挥谱元(spectral element,SE)法可快速高效求解三维地震波场传播和多自由度(multi-degree of freedo... 场地-城市相互作用(site-city interaction,SCI)效应会显著改变场地地震波场分布及建筑反应,基于SCI效应理论计算研究方法的发展现状,发挥谱元(spectral element,SE)法可快速高效求解三维地震波场传播和多自由度(multi-degree of freedom,MDOF)模型计算量小且可同时模拟大量建筑的优势,同时,结合频率波数域(frequency wave number analysis,FK)方法,以等效地震荷载的方式施加地震波场,建立了FK-SE-MDOF耦合方法,实现了SE-MDOF耦合模型中多种波型(P波、SV波和SH波)的斜入射输入,解决了当前三维SCI效应研究方法中未能同时考虑建筑非线性、频谱特性、地震波波型及入射角度影响的问题。首先对方法原理进行了介绍;然后,通过与振动台试验的对比,验证了方法的正确性;进而,采用该方法建立理想场地-城市建筑群相互作用耦合模型,主要探讨了入射角度和地震波波型对SCI效应的影响,得到了一些有益结论。该方法较为真实地反映SCI效应影响的同时,可反映建筑基础轮廓对地震波场的影响,适用于需考虑建筑轮廓信息的社区尺度SCI效应研究,可为城市规划、抗震设计、风险评估以及震后救援等工作提供定量指导。 展开更多
关键词 场地-城市相互作用(SCI) 频率波数域-谱元-多自由度模型(FK-SE-MDOF)方法 斜入射 建筑群 社区尺度
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老年股骨颈骨折全髋或半髋关节置换的中远期状态:倾向性评分匹配法评价 被引量:2
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作者 李志鹏 环大维 +4 位作者 袁兆丰 丁凯 邱越 夏天卫 沈计荣 《中国组织工程研究》 CAS 北大核心 2024年第24期3839-3844,共6页
背景:关节置换是治疗老年移位性股骨颈骨折的主要手段,全髋关节置换与半髋关节置换的选择是目前具有较大争论的焦点。目的:基于倾向性评分匹配法对比直接前入路下全髋与半髋关节置换治疗老年移位性股骨颈骨折的中远期生存状态。方法:选... 背景:关节置换是治疗老年移位性股骨颈骨折的主要手段,全髋关节置换与半髋关节置换的选择是目前具有较大争论的焦点。目的:基于倾向性评分匹配法对比直接前入路下全髋与半髋关节置换治疗老年移位性股骨颈骨折的中远期生存状态。方法:选择2016年1月至2021年1月收治的147例老年移位性股骨颈骨折患者(≥65岁),其中88例行全髋关节置换,59例行人工股骨头置换(半髋关节置换)。对于患者术前合并症采用年龄校正Charlson合并症评分表,计算患者虚弱度,并采用倾向性评分匹配法对两组患者进行1∶1匹配,比较匹配后两组患者的手术时间、出血量、术后住院时间、住院费用、营养指标、术后并发症、死亡率和术后生存时间,其中术后生存时间采用Kaplan-Meier生存分析。结果与结论:①倾向性评分匹配后,两组共有42对匹配成功,匹配后两组患者术前资料均衡可比(P>0.05);②与半髋关节置换组相比,全髋关节置换组手术时间(79.71 min vs.59.07 min,P<0.001)、出血量(839.64 mL vs.597.83 mL,P=0.001)、住院费用(56508.15元vs.41702.85元,P<0.001)明显增加,但全髋关节置换组死亡率低于半髋关节置换组(36%vs.57%,HR=0.44,95%CI:0.23-0.87,P=0.018),平均生存时间长于半髋关节置换组(59.4个月vs.43.7个月,P=0.024);③两组患者在术后住院时间、术前术后营养指标、术后整体并发症发生率上,差异均无显著性意义(P>0.05);但在术后疼痛方面,半髋关节置换组疼痛发生率明显高于全髋关节置换组(24%vs.7%,P=0.035);④整体来看,全髋关节置换具有更好的长期预后生存效果,但对于身体素质差的患者则更适合行半髋关节置换;同时,术后的疼痛可能很大程度上会对患者髋关节置换后的生活质量及存活时间产生影响。 展开更多
关键词 直接前入路 移位性股骨颈骨折 老年 全髋关节置换 半髋关节置换 年龄校正Charlson合并症评分 倾向性评分匹配 生存状态
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新时代边疆绿色空间的概念内涵、尺度级联与重构路径
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作者 史云贵 刘璐瑶 《云南师范大学学报(哲学社会科学版)》 CSSCI 北大核心 2024年第4期1-9,共9页
边疆绿色空间是指边疆多元治理主体秉持绿色价值理念,在边疆自然、社会、经济、文化等领域进行“绿化”实践的生态场域,是能够容纳和生产以“绿色”为底蕴的绿色生态、绿色政治、绿色经济、绿色文化等诸多美好要素的空间。边疆绿色空间... 边疆绿色空间是指边疆多元治理主体秉持绿色价值理念,在边疆自然、社会、经济、文化等领域进行“绿化”实践的生态场域,是能够容纳和生产以“绿色”为底蕴的绿色生态、绿色政治、绿色经济、绿色文化等诸多美好要素的空间。边疆绿色空间重构是顺应时代潮流和回应边疆人民美好生活诉求的空间发展策略,也是融入国家整体发展战略,实现边疆高质量发展和绿色转型的必由之道。进入新时代,面对空间要素跨尺度流动持续加速、流动范围不断扩大的发展趋势,应将多尺度空间级联效应纳入我国边疆绿色空间重构的考虑范畴;基于边疆绿色空间尺度重组过程,识别不同空间尺度的发展目标,构建驱动边疆多尺度绿色空间重构的“尺度重组——尺度级联——空间重构”重构策略和重构路径,不断推动边疆多尺度绿色空间的耦合协同发展,构建面向边疆绿色空间可持续发展的多尺度级联福祉保障。 展开更多
关键词 边疆绿色空间 空间重构 尺度重组 尺度级联 重构路径
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乳晕入路腔镜甲状腺切除术与开放性甲状腺切除术治疗甲状腺癌患者的效果比较
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作者 秦向阳 《中国民康医学》 2024年第6期139-141,共3页
目的:比较乳晕入路腔镜甲状腺切除术与开放性甲状腺切除术治疗甲状腺癌患者的效果。方法:选取2021年7月至2023年1月该院收治的82例甲状腺癌患者进行前瞻性研究,按照随机数字表法将其分为观察组与对照组各41例。对照组行开放性甲状腺切... 目的:比较乳晕入路腔镜甲状腺切除术与开放性甲状腺切除术治疗甲状腺癌患者的效果。方法:选取2021年7月至2023年1月该院收治的82例甲状腺癌患者进行前瞻性研究,按照随机数字表法将其分为观察组与对照组各41例。对照组行开放性甲状腺切除术治疗,观察组行经乳晕入路腔镜甲状腺切除术治疗。比较两组手术时间、术中出血量、住院时间、术后引流量,手术前后嗓音障碍指数(VHI)和吞咽障碍评分量表(SIS)评分,以及并发症发生率。结果:观察组手术时间、住院时间短于对照组,术中出血量、术后引流量少于对照组,差异均有统计学意义(P<0.05);术后3 d,两组VHI和SIS评分低于术前,且观察组低于对照组,差异均有统计学意义(P<0.05);两组并发症发生率比较,差异无统计学意义(P>0.05)。结论:乳晕入路腔镜甲状腺切除术治疗甲状腺癌患者可减少或降低术中出血量、术后引流量、SIS评分、VHI评分和并发症发生率,缩短手术时间和住院时间,效果优于开放性甲状腺切除术治疗。 展开更多
关键词 乳晕入路 甲状腺癌 甲状腺切除术 吞咽障碍评分量表评分 嗓音障碍指数评分 并发症
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弱小目标低对比度图像增强算法研究 被引量:7
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作者 雍杨 王敬儒 张启衡 《激光与红外》 CAS CSCD 北大核心 2005年第5期370-373,共4页
采用分段线性变换对白天亮背景下低对比度图像序列进行对比度增强,最关键的是分段点的选取。提出两种分段点确定方法:多尺度逼近利用目标和背景的灰度值在不同尺度空间中具有不同动态特性的特点,逐次逼近,通过找出目标和背景的过渡区域... 采用分段线性变换对白天亮背景下低对比度图像序列进行对比度增强,最关键的是分段点的选取。提出两种分段点确定方法:多尺度逼近利用目标和背景的灰度值在不同尺度空间中具有不同动态特性的特点,逐次逼近,通过找出目标和背景的过渡区域得到分段点;恒增强率方法确定一个固定的增强率,在直方图中由高到低找出满足该比率的灰度值作为分段点。两种方法均简单易行,试验证明它们能准确地对分段点进行定位,从而有效地增强了图像的对比度。 展开更多
关键词 低对比度图像 图像增强 多尺度逼近 恒增强率
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中国土地利用/土地覆盖的多尺度空间分布特征分析 被引量:151
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作者 陈佑启 PeterH.Verburg 《地理科学》 CSCD 北大核心 2000年第3期197-202,共6页
研究了我国土地利用影响因素及其空间规模相关性,采用数理统计与GIS手段从多个规模尺度上探讨了我 国土地利用的空间分布特征。其结果对全国以及各级政府进行土地利用规划、制定相应的土地开发与利用政策等 具有一定的参考意义。
关键词 土地利用 土地覆盖 多尺度分析 空间分布特征
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工程选址的“安全岛”多级逼近与优选理论 被引量:18
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作者 刘传正 胡海涛 《中国地质灾害与防治学报》 CSCD 1993年第1期30-39,64,共11页
在回顾重大工程区域地壳稳定性研究历史,分析其面临的挑战的基础上,经过论证活动构造区的特点及强震区大坝建筑的经验,结合当前工程建设要求和全球活动构造学研究现状,作者初步建立了重大工程选址的“安全岛”多级逼近与优选理论体系和... 在回顾重大工程区域地壳稳定性研究历史,分析其面临的挑战的基础上,经过论证活动构造区的特点及强震区大坝建筑的经验,结合当前工程建设要求和全球活动构造学研究现状,作者初步建立了重大工程选址的“安全岛”多级逼近与优选理论体系和工作步骤,讨论了其自然哲学和板块构造学基础,进一步发展了由李四光(1965,1967)提出,胡海涛(1979,1984,1988)坚持并发展起来的“安全岛”理论。多级逼近与优选的大意是,根据边界断裂的规模、活动方式或强度与地块内部性状的基本一致性,从大到小逐级确定出一系列地块,并在每级的若干地块中优选出相对稳定者即“安全岛”。提出了用稳定度(Δf)概念描述“安全岛”的稳定程度,并用模式识别方式进行量化表达。为反映“安全岛”的地质地震历史状态,提出据安全期概念建立“安全岛”的工程分类,即分为永久稳定的、相对稳定的和暂时稳定的三类。 展开更多
关键词 工程选址 安全岛 多级逼近与优选理论 安全期 稳定度
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运用多尺度法对齿轮系统组合共振特性的分析 被引量:6
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作者 王建平 王玉新 《西安理工大学学报》 CAS 2005年第1期5-10,共6页
在考虑了啮合时变刚度、齿侧间隙、传递误差等多种非线性因素的基础上,应用多尺度分析方法对单对直齿轮传动系统的组合共振特性进行了研究。在分析模型中,将时变刚度按5次谐波展开,齿侧间隙按3次多项式拟合。研究了系统在内部激励、外... 在考虑了啮合时变刚度、齿侧间隙、传递误差等多种非线性因素的基础上,应用多尺度分析方法对单对直齿轮传动系统的组合共振特性进行了研究。在分析模型中,将时变刚度按5次谐波展开,齿侧间隙按3次多项式拟合。研究了系统在内部激励、外部激励和参数激励作用下组合共振的激振频率组合方式,得到了稳态振动的频率响应方程,并绘制了相应的频率响应曲线,指出静态激励、动态激励、内部激励、外部激励对系统共振响应的不同影响作用。 展开更多
关键词 多尺度法 时变刚度 传递误差 间隙 组合共振
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横向补给系统高架索横向振动研究 被引量:2
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作者 张良欣 何学军 任爱娣 《应用基础与工程科学学报》 EI CSCD 2010年第3期523-529,共7页
考虑了集中质量对系统动力学行为的影响,基于弹性力学理论,建立了海上横向补给系统高架索的横向振动的连续体理论模型.利用Galerkin方法对高架索系统振动的偏微分方程进行模态离散,忽略高阶模态影响,得到了高架索系统的标准非线性动力... 考虑了集中质量对系统动力学行为的影响,基于弹性力学理论,建立了海上横向补给系统高架索的横向振动的连续体理论模型.利用Galerkin方法对高架索系统振动的偏微分方程进行模态离散,忽略高阶模态影响,得到了高架索系统的标准非线性动力学控制方程.利用多尺度方法对动力学方程进行渐近分析,研究结果表明高架索横向振动除了受高架索张力影响外,同时还受集中质量大小、位置等因素的影响. 展开更多
关键词 非线性动力学 GALERKIN方法 多尺度方法 高架索 横向补给
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