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Relation between the evolution of seismic apparent strain field and the region of strong earthquake occurrence 被引量:3
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作者 黄福明 易志刚 《Acta Seismologica Sinica(English Edition)》 EI CSCD 2000年第6期616-627,共12页
In this paper, according to the data on the middle and strong earthquakes in China, we have preliminary studied the relation between the characteristic of space-time evolution of the seismic apparent strain field and ... In this paper, according to the data on the middle and strong earthquakes in China, we have preliminary studied the relation between the characteristic of space-time evolution of the seismic apparent strain field and the regions of 31 macroseism events since 1955. The result shows that, there is a rather well correlation between the anomaly region of seismic apparent strain and the zone of macroseism event occurrence within the time range of one to about five years. The R value of the application of the abnormal region of seismic apparent strain to predicting the area of strong earthquake occurrence is 0.458, and the empirical possibility of forecasting the region of macroseism occurrence is 0.625, and so the forecasting effect is comparatively well. Finally, the main results obtained above are discussed preliminarily. 展开更多
关键词 seismic apparent strain anomaly region EVOLUTION region of macroseism occurrence earthquake prediction R valu?
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Assessment of Regional Myocardial Function in Patients with Hypertrophic Cardiomyopathy by Tissue Strain Imaging 被引量:2
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作者 熊润青 谢明星 +1 位作者 王新房 吕清 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2006年第3期334-337,共4页
The value of tissue strain imaging (SI) in regional myocardial systolic and diastolic func tion assessment was studied. In 18 patients with nonobstructive hypertrophic cardiomyopathy (HCM) and 20 age-matched healt... The value of tissue strain imaging (SI) in regional myocardial systolic and diastolic func tion assessment was studied. In 18 patients with nonobstructive hypertrophic cardiomyopathy (HCM) and 20 age-matched healthy subjects, regional myocardial longitudinal peak systolic strain in eject time (represented by εet) was measured at basal, mid and apical segments of septal, lateral and posterior walls of the left ventricle (LV) and compared between groups, εet had no significant difference between segments in control group (P〉0.05), which displayed a decreasing trend from basal segments to apical ones. εet in the HCM group was significantly decreased (P(0. 05) as compared with that in the healthy group. In the HCM group, εet in the midseptum was significantly less than at the basal and apical septum, and was also less than at the rest LV walls in the same group (P〉0.01). The systolic reversed εet was noticed in 35% of the hypertrophic segments in HCM group. Significantly negative correlation existed between the absolute value of εet and wall thickness in the midseptum (r= -0.83). The post-systolic strain(PSS) segment number the and amplitudes in healthy group were significantly less than those in HCM group (P〈0.05). Both regional myocardial systolic and diastolic functions were impaired in hypertrophic or non-hypertrophic segments in patients with the HCM, especially in hypertrophic segments. Strain imaging technique is a sensitive and accura tool in myocardial dysfunction assessment. 展开更多
关键词 ECHOCARDIOGRAPHY tissue strain imaging hypertrophic cardiomyopathy regional myocardial function
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Ballistic Transport through a Strained Region on Monolayer Phosphorene
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作者 Yi Ren Fang Cheng 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第2期96-99,共4页
We investigate quanturn transport of carriers through a strained region on monolayer phosphorene theoretically. The electron tunneling is forbidden when the incident angle exceeds a critical value. The critical angles... We investigate quanturn transport of carriers through a strained region on monolayer phosphorene theoretically. The electron tunneling is forbidden when the incident angle exceeds a critical value. The critical angles for electrons tunneling through a strain region for different strengths and directions of the strains are different. Owing to the anisotropic effective masses, the conductance shows a strong anisotropic behavior. By tuning the Fermi energy and strain, the channels can be transited from opaque to transparent, which provides us with an efiqcient way to control the transport of monolayer phosphorene-based microstruetures. 展开更多
关键词 Ballistic Transport through a strained region on Monolayer Phosphorene
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REGION-WISE VARIATIONAL PRINCIPLES AND GENERALIZED VARIATIONAL PRINCIPLES ON LARGE STRAIN FOR CONSOLIDATION THEORY
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作者 罗晓辉 李永乐 罗昕 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2005年第7期944-952,共9页
The difference of constitutive character and large deformation as to soil mass are basic questions to analyze deformational feature. According to the description method of limited deformation, the large deformation co... The difference of constitutive character and large deformation as to soil mass are basic questions to analyze deformational feature. According to the description method of limited deformation, the large deformation consolidation equations of soil mass were created and its variational principles were rigorously testified. The regionwise variational principles of consolidation theory were deduced using sub-structure continuous condition of region-wise. Quoting the method of Lagrangian multiplier operator, generalized variational principles of region-wise of large deformation consolidation in the nonconstrained condition were created and approved. 展开更多
关键词 large strain consolidation variational principle region-wise variation generalized variational principle
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Horizontal movement and strain characteristics in Tianshan and its adjacent region with GPS deformation data
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作者 王晓强 李杰 +1 位作者 Alexander Zubovich 王琪 《Acta Seismologica Sinica(English Edition)》 CSCD 2007年第1期33-39,共7页
Based on the multiple-term horizontal velocity solutions of 230 GPS monitoring sites in Tianshan and its adjacent region, the GPS site velocity fields and crustal horizontal strain fields in the area have been obtaine... Based on the multiple-term horizontal velocity solutions of 230 GPS monitoring sites in Tianshan and its adjacent region, the GPS site velocity fields and crustal horizontal strain fields in the area have been obtained. The results show that the crustal shortening rate of Tianshan, with the longitude (77°±1°)E as the boundary, gradually decreased towards two sides, from the south to the north, indicating that the pushing force of plate becomes weaker along with the fold deformation decreasing of the Tianshan. The direction of principal compressive strain of Tianshan and its adjacent area, nearly NNW, is basically perpendicular to the Tianshan cordillera trend, suggesting the distribution and variation of maximum principal compressive stress in Tianshan and its adjacent region resulted from collision and extrusion of Indian Plate. This paper indicates that the maximum shear strain field mainly con- centrates on two areas, one is Isyk lake of North Tianshan, Kyrgyzstan, and the other is the juncture of Jiashi (South Tianshan) and Pamir arc faults. In the above areas, it can be shown from the epicentral distribution that the strong earthquakes mostly occurs at the high shearing strain accumulation filed or its edge. 展开更多
关键词 GPS Tianshan and its adjacent region horizontal strain rate filed maximum shear strain
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Study on Relation Between Dynamic Pattern of Regional Vertical Strain Rate and Several Strong Earthquakes such as Lijiang(M_s7.0)and Menyuan(M_s6.4)Earthquakes
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作者 Wang Shuangxu Jiang Zaisen +1 位作者 Zhang Xi Chen Bing 《Earthquake Research in China》 2000年第3期30-41,共12页
Making use of the method of obtaining regional vertical strain rate from regional preciseleveling data and gaining dynamic pattern combining with deformation data on spanningfaults, the regional vertical strain dynami... Making use of the method of obtaining regional vertical strain rate from regional preciseleveling data and gaining dynamic pattern combining with deformation data on spanningfaults, the regional vertical strain dynamic evolution characteristics of several moderatelystrong earthquakes such as Lijiang (M_s 7.0) and Menyuan (M_s 6.4) earthquakes occurredin crustal deformation monitoring areas located in the western Yunnan and Qilianshan-Hexiregion. Based on the above-mentioned facts, by studying the time-space nonhomogeneity andstrain energy accumulation status, some criteria for judging the medium. and short-termstrong seismic risk regions according to the regional vertical strain rate dynamic informationare proposed. 展开更多
关键词 regional VERTICAL strain rate DYNAMIC PATTERN evolution characteristics Medium- and short-term prediction criterion of strong EARTHQUAKES
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Euler-Lagrange Elasticity: Differential Equations for Elasticity without Stress or Strain 被引量:1
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作者 H. H. Hardy 《Journal of Applied Mathematics and Physics》 2013年第7期26-30,共5页
Differential equations to describe elasticity are derived without the use of stress or strain. The points within the body are the independent parameters instead of strain and surface forces replace stress tensors. The... Differential equations to describe elasticity are derived without the use of stress or strain. The points within the body are the independent parameters instead of strain and surface forces replace stress tensors. These differential equations are a continuous analytical model that can then be solved using any of the standard techniques of differential equations. Although the equations do not require the definition stress or strain, these quantities can be calculated as dependent parameters. This approach to elasticity is simple, which avoids the need for multiple definitions of stress and strain, and provides a simple experimental procedure to find scalar representations of material properties in terms of the energy of deformation. The derived differential equations describe both infinitesimal and finite deformations. 展开更多
关键词 ELASTICITY STRESS strain INFINITESIMAL Deformations Finite Deformations Discrete region Model
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Effect of <i>pyk</i>gene location on constructing dATP conversion <i>E. coli</i>strain
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作者 Xiujuan Xin Jie Bao 《Advances in Bioscience and Biotechnology》 2013年第1期75-80,共6页
A dATP conversion E. coli strain could be constructed when both pyk and adk1 gene were expressed successfully. pyk gene encodes pyruvate kinase (PK) could be expressed, when inserted it before adk1 gene which encodes ... A dATP conversion E. coli strain could be constructed when both pyk and adk1 gene were expressed successfully. pyk gene encodes pyruvate kinase (PK) could be expressed, when inserted it before adk1 gene which encodes adenylate kinase (AK) in plasmid pET-pyk-adk1 after transform into E. coli and the recombinant could be used to convert dATP from dAMP. Another plasmid pET-adk1-pyk, which inserted pyk gene behind of adk1, the recombinant E. coli transformed with this plasmid could not convert dAMP into dATP, pyk gene cannot be translated in this recombinant. The different translation levels of pyk with gene location switching caused mainly by the different secondary structures formed by the 5’-untranslation regions and the gene sequence of its5’-terminal. The dATP product E. coli strain could be constructed when cloned pyk gene at an optimum location. 展开更多
关键词 pyk Gene Location dATP CONVERSION strain 5-Untranslation regions
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An Explicit Surface-Potential Based Biaxial Strained-Si n-MOSFET Model for Circuit Simulation 被引量:1
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作者 Tapas K. Maiti Animesh Banerjee Chinmay K. Maiti 《Engineering(科研)》 2010年第11期879-887,共9页
In this paper, a charge sheet surface potential based model for strained-Si nMOSFETs is presented and validated with numerical simulation. The model considers sub band splitting in the 2-DEG at the top heterointerface... In this paper, a charge sheet surface potential based model for strained-Si nMOSFETs is presented and validated with numerical simulation. The model considers sub band splitting in the 2-DEG at the top heterointerface in SiGe layer and also the dependence of electron concentration at heterointerface with the gate oxide. The model is scalable with strained-Si material parameters with physically derived flat-band voltages. An explicit relation for surface potential as a function of terminal voltages is developed. The model is derived from regional charge-based approach, where regional solutions are physically derived. The model gives an accurate description of drain current both in the weak and strong inversion regions of operation. The results obtained from the model developed are benchmarked with commercial numerical device simulator and is found to be in excellent agreement. 展开更多
关键词 strainED-SI HETEROSTRUCTURE 2-DEG SURFACE POTENTIAL regional Approach
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茄衣新品系川雪2号全国多点试验研究
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作者 何正川 刘勇 +9 位作者 阳苇丽 韦树谷 杜卫民 王要君 肖洁 盛玉珍 尹宏博 何炼 魏建均 代顺冬 《安徽农业科学》 CAS 2024年第13期22-26,共5页
为雪茄烟茄衣新品系川雪2号的品种审定、推广提供科学依据。以川雪2号及其他8份雪茄烟品系为试验材料,2021年在全国9个主要雪茄烟产区、2022年在全国8个主要雪茄烟产区开展多点试验。结果表明,川雪2号田间整齐、长势强,大田生育期88 d... 为雪茄烟茄衣新品系川雪2号的品种审定、推广提供科学依据。以川雪2号及其他8份雪茄烟品系为试验材料,2021年在全国9个主要雪茄烟产区、2022年在全国8个主要雪茄烟产区开展多点试验。结果表明,川雪2号田间整齐、长势强,大田生育期88 d、免疫TMV、抗根黑腐病、综合抗病能力较强、田间自然发病率整体较轻;平均产量为1533.30 kg/hm^(2),平均产值为83234.70元/hm^(2),中上等烟比例为74.98%,产量、产值、中上等烟比例、评吸总分等在9个参试品系中排名靠前。川雪2号总体表现较好,可以进行一定规模的示范种植并开展相关配套栽培技术研究。 展开更多
关键词 茄衣 品系 川雪2号 多点试验
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2021年榆林市谷子新品系区域试验
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作者 霍瑞锋 井苗 +2 位作者 王孟 李振姣 李海录 《园艺与种苗》 CAS 2024年第2期79-80,83,共3页
[目的]鉴定评价新选育的谷子品系的适应性、丰产性、稳产性、抗逆性,筛选出适宜在当地推广种植的新品种。[方法]在榆林地区试验点对育成的9个谷子品系进行区域试验,研究其丰产性、稳产性、经济性状、农艺性状、抗逆性。[结果]筛选出适... [目的]鉴定评价新选育的谷子品系的适应性、丰产性、稳产性、抗逆性,筛选出适宜在当地推广种植的新品种。[方法]在榆林地区试验点对育成的9个谷子品系进行区域试验,研究其丰产性、稳产性、经济性状、农艺性状、抗逆性。[结果]筛选出适宜在榆林及其周边地区推广种植的谷子新品系榆谷10(2014YH-1)和榆谷12(K2021-11)。[结论]该试验可为榆林地区谷子新品种示范推广提供依据。 展开更多
关键词 谷子 新品系 区域试验 榆林
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四川地区YRY-4型钻孔应变观测资料可靠性分析
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作者 徐亚飞 张菊 +4 位作者 周朝晖 张晓明 张小东 徐建明 阳光 《四川地震》 2024年第3期30-35,共6页
通过分析钻孔应变观测资料的干扰因素,发现四川地区YRY-4型钻孔应变受季节性降雨、钻孔水位和河水位涨落影响显著。采用钻孔应变自洽检验对钻孔应变仪观测数据进行自检,发现各台应变校正相关系数均大于0.9,说明四川地区YRY-4型应变观测... 通过分析钻孔应变观测资料的干扰因素,发现四川地区YRY-4型钻孔应变受季节性降雨、钻孔水位和河水位涨落影响显著。采用钻孔应变自洽检验对钻孔应变仪观测数据进行自检,发现各台应变校正相关系数均大于0.9,说明四川地区YRY-4型应变观测资料的整体质量较高,可以用于区域地震预测和地震科学研究。 展开更多
关键词 四川地区 YRY-4钻孔应变 自洽检验 可靠性
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南疆地区不同冬小麦品种比较试验
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作者 杨秋侠 黄鑫 +3 位作者 杨志刚 李字辉 张慧 张健 《安徽农学通报》 2024年第19期13-17,共5页
为鉴定、引进和选育适宜南疆地区的冬小麦品种,本研究在该地区共设泽普(D_(1))、新和(D_(2))、农一师(D3)等8个试验点,以新冬60号(CK_(1))、新冬20号(CK_(2))为对照品种,对新粮809、阿农冬9号、新粮807、新粮808、九圣禾D1809和金丰源麦... 为鉴定、引进和选育适宜南疆地区的冬小麦品种,本研究在该地区共设泽普(D_(1))、新和(D_(2))、农一师(D3)等8个试验点,以新冬60号(CK_(1))、新冬20号(CK_(2))为对照品种,对新粮809、阿农冬9号、新粮807、新粮808、九圣禾D1809和金丰源麦3号等20个小麦品种开展品种(系)比较试验,对其群体结构和分蘖成穗特性、主要穗部性状和农艺性状、丰产性及其稳定性进行分析。结果表明,九圣和D1809、普冰资017、新粮807和新粮808的群体结构和分蘖成穗综合表现较好;金丰源麦3号、阿农冬9号、新粮807、新粮809和九圣禾D1809等9个品种的平均产量较对照品种新冬20号和新冬60号增产幅度均在5%以上,且金丰源麦3号、新粮807、新粮809和九圣禾D1809丰产性和稳产性较好,可在该地区进一步示范种植。 展开更多
关键词 南疆地区 冬小麦 产量 品种比较
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基于Kaiser效应的地应力差应变测试及区域地应力分布研究
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作者 赵龙 乔伟 +6 位作者 程香港 贺虎 孟祥胜 张玉生 孙文杰 任洋洋 肖冲 《煤矿安全》 CAS 北大核心 2024年第10期91-99,共9页
以往差应变分析法(DSA)通过估算垂向主应力以求解地应力,使得该方法可靠性较差。基于岩石试样的Kaiser效应,结合差应变法,提出了一种基于Kaiser效应的地应力差应变测试方法(Kaiser-DSA法),并利用Kaiser-DSA法与应力解除法进行了对比,表... 以往差应变分析法(DSA)通过估算垂向主应力以求解地应力,使得该方法可靠性较差。基于岩石试样的Kaiser效应,结合差应变法,提出了一种基于Kaiser效应的地应力差应变测试方法(Kaiser-DSA法),并利用Kaiser-DSA法与应力解除法进行了对比,表明Kaiser-DSA法测试结果与应力解除法的测试结果相对误差小,且最大水平主应力方向基本一致;基于地应力测试结果,分析了窑街矿区地应力分布规律,探究了窑街矿区现今地应力场成因。结果表明:窑街矿区区域上受到了挤压构造应力场的作用,残余应力较高;受青藏逆冲推覆作用与F19断层的顺时针剪切作用,该区域地应力场以σH(最大水平主应力)>σv(垂向主应力)>σh(最小水平主应力)型的走滑型应力状态为主;此外,较高的差应力使得该区域回采时围岩体变形破坏严重,动力灾害事件频发。 展开更多
关键词 KAISER效应 差应变分析 地应力测试 窑街矿区 区域构造演化
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考虑横隔板局部刚域的宽幅钢-混组合梁桥荷载试验研究
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作者 周丽芹 张家琪 +1 位作者 刘国华 王路 《价值工程》 2024年第26期144-147,共4页
在主梁高度既定的情况下,长宽比大的桥梁横向抗弯刚度相对较大,桥面荷载横向分布对主梁应变及挠度在横桥向的响应程度影响较小;但对于长宽比小的宽幅桥梁,桥梁整体的横向抗弯刚度对应变及挠度的分布影响会急剧增大,对于分离式主梁桥梁,... 在主梁高度既定的情况下,长宽比大的桥梁横向抗弯刚度相对较大,桥面荷载横向分布对主梁应变及挠度在横桥向的响应程度影响较小;但对于长宽比小的宽幅桥梁,桥梁整体的横向抗弯刚度对应变及挠度的分布影响会急剧增大,对于分离式主梁桥梁,传统的梁格法荷载试验模型在模拟横向抗弯刚度时会产生误差,影响最终的检验结果评判精度。本文以宽幅钢-混组合梁桥荷载试验为例,采用梁格法模型计算了横隔板与主梁交接处局部刚域对理论应变和挠度横向分布的影响,结合板单元+实体单元模型和现场实测数据进行对比分析,研究结果可为宽幅分离式主梁桥梁的荷载试验及有限元模型修正提供参考。 展开更多
关键词 宽幅桥梁 荷载试验 梁格法 局部刚域 应变和挠度
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不同区域粉土累积塑性应变预测模型
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作者 余虔 曹正龙 +2 位作者 寇璟媛 高妍婕 马新岩 《公路交通科技》 CAS CSCD 北大核心 2024年第7期56-64,共9页
机场道基在长期服役过程中,不同区域粉土的累积塑性应变发展有显著差异。目前研究中鲜有考虑粉土区域性差异影响,尚未有预测模型能够对不同区域机场的道基粉土进行统一量化和预测。为确定影响粉土累积塑性应变的关键指标,有针对性地预... 机场道基在长期服役过程中,不同区域粉土的累积塑性应变发展有显著差异。目前研究中鲜有考虑粉土区域性差异影响,尚未有预测模型能够对不同区域机场的道基粉土进行统一量化和预测。为确定影响粉土累积塑性应变的关键指标,有针对性地预测各区域粉土塑性应变,保证道基的长期服役性能,从华北地区3个不同机场取现场道基粉土,开展了不同区域和不同黏粒含量下粉土的动三轴试验,以揭示了不同条件下粉土累积塑性应变发展规律;通过SPSS灰色关联分析探究了不同区域粉土的矿物成分、颗粒级配、液塑限、最优含水率和最大干密度等指标与其循环荷载下最终累积应变的相关性,确定了黏粒含量为关键评价指标;基于试验结果建立了最终累积塑性应变预测模型。结果表明:不同区域粉土的颗粒级配、液塑限和最大干密度均有显著差异;循环荷载下累积塑性应变也差异显著,且受动应力影响;通过灰色关联分析,确定了以黏粒含量作为评价各地粉土最终累积塑性应变的量化指标;基于不同黏粒含量的动三轴试验结果,建立了考虑区域差异和动应力幅值的最终累积塑性应变预测模型。该预测模型能较好适用于不同区域机场道基粉土,基于当地粉土黏粒含量情况,较为准确地预测其长期服役过程中的累积塑限应变。 展开更多
关键词 道路工程 累积塑性应变 动三轴试验 粉土区域性差异 黏粒含量 灰色关联分析
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补中益气汤联合肛周局部注射在中气下陷型肛门坠胀患者中的应用
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作者 刘海涛 倪晓会 《世界复合医学(中英文)》 2024年第7期1-4,13,共5页
目的探讨补中益气汤联合肛周局部注射在中气下陷型肛门坠胀患者中的临床应用价值。方法选择2021年11月—2023年7月泰安市中医二院收治的80例中气下陷型肛门坠胀患者为研究对象,按照不同治疗方案分为两组,各40例。对照组给予局部肛周注射... 目的探讨补中益气汤联合肛周局部注射在中气下陷型肛门坠胀患者中的临床应用价值。方法选择2021年11月—2023年7月泰安市中医二院收治的80例中气下陷型肛门坠胀患者为研究对象,按照不同治疗方案分为两组,各40例。对照组给予局部肛周注射,观察组在对照组治疗的基础上联合服用补中益气汤治疗。比较两组治疗前后韦克斯纳尿失禁量表(Wexner Incontinence Scale,Wexner)评分、肛门坠胀程度评分、每日肛门坠胀持续时间、静息时肛直角和每日排便次数、治疗后排尿障碍、排便障碍及肛门失禁情况。结果治疗后,观察组Wexner评分为(10.4±2.7)分,低于治疗前观察组的(15.3±4.6)分及治疗后对照组的(12.7±3.3)分,差异有统计学意义(t=5.810、3.412,P均<0.05)。观察组肛门坠胀程度评分低于对照组,每日肛门坠胀持续时间短于对照组,差异有统计学意义(P均<0.05)。观察组静息时肛直角小于对照组,每日排便次数少于对照组,差异有统计学意义(P均<0.05)。观察组治疗后存在的排尿障碍、排便障碍及肛门失禁总比例低于对照组,差异有统计学意义(P<0.05)。结论针对中气下陷型肛门坠胀患者,在应用肛周局部注射同时联合补中益气汤进行干预,可改善患者临床症状,缩短肛门不适时间,促进排便功能恢复。 展开更多
关键词 补中益气汤 肛周 局部注射 中气下陷型 肛门坠胀
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超声斑点追踪技术对心肌梗死患者室壁运动的二维应变研究 被引量:47
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作者 熊莉 邓又斌 +4 位作者 申屠伟慧 余芬 张芸 黄润青 张清阳 《中国医学影像技术》 CSCD 北大核心 2007年第7期990-993,共4页
目的应用超声斑点追踪技术测量心肌梗死患者梗死节段室壁的二维应变,探讨其诊断局部室壁运动异常的临床应用价值。方法30例正常人及30例心肌梗死患者,分别记录左室短轴(二尖瓣,乳头肌,心尖部)图像和心尖位四腔切面,二腔切面,左室长轴高... 目的应用超声斑点追踪技术测量心肌梗死患者梗死节段室壁的二维应变,探讨其诊断局部室壁运动异常的临床应用价值。方法30例正常人及30例心肌梗死患者,分别记录左室短轴(二尖瓣,乳头肌,心尖部)图像和心尖位四腔切面,二腔切面,左室长轴高帧频图像,应用二维应变软件测量各个节段的二维应变值。结果心肌梗死患者梗死节段共177个,其中158个节段通过超声斑点追踪技术,获得二维应变值。基底段,中间段及心尖段纵向应变值与正常对照组均明显减低,有显著性差异,P<0.01;左室短轴(二尖瓣,乳头肌及心尖部水平)的径向应变及圆周应变与正常对照组均明显减低,有显著性差异,P<0.05;旋转角度无统计学差异。结论超声斑点追踪技术可准确评价节段性室壁运动异常,为临床评价心肌梗死患者左心收缩功能提供无创性新方法. 展开更多
关键词 超声心动图描记术 二维应变 节段性室壁运动异常 心室功能
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压力容器高应变区应变疲劳裂纹扩展试验研究 被引量:9
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作者 陈学东 杨铁成 +1 位作者 蒋家羚 李培宁 《实验力学》 CSCD 北大核心 2003年第4期520-528,共9页
针对压力容器几何结构不连续高应变区断裂和疲劳破坏特点,本文通过对应变循环条件下疲劳裂纹扩展影响因素和控制参量的理论分析,提出将ΔJ作为应变循环条件下疲劳裂纹扩展速率的控制参量,并在EPRI弹塑性断裂分析工程方法基础上,提出了Δ... 针对压力容器几何结构不连续高应变区断裂和疲劳破坏特点,本文通过对应变循环条件下疲劳裂纹扩展影响因素和控制参量的理论分析,提出将ΔJ作为应变循环条件下疲劳裂纹扩展速率的控制参量,并在EPRI弹塑性断裂分析工程方法基础上,提出了ΔJ的工程计算方法,并通过模拟应变疲劳裂纹扩展的SCT试样试验,验证了ΔJ工程计算方法的可靠性.根据SCT试样应变疲劳裂纹扩展试验研究结果,在考虑了压力容器高应变区几何形状和材质变化对应变疲劳裂纹扩展参量影响后,提出了一种压力容器高应变区应变疲劳裂纹扩展速率工程估算方法. 展开更多
关键词 压力容器 应变疲劳 高应变区 裂纹扩展 应变梯度 控制参量 循环加载
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超声二维斑点追踪技术定量评价不同部位心肌梗死患者心功能的研究 被引量:9
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作者 张慧 王禹 +6 位作者 王秋霜 张梅青 姬冬冬 孟娟娟 张丽伟 沈东 张春红 《中国康复理论与实践》 CSCD 2010年第4期349-351,共3页
目的探讨对于不同部位心肌梗死,超声二维斑点追踪技术定量判断局部室壁运动异常及心脏整体收缩功能状态的临床应用价值。方法二维超声记录左室长轴和短轴切面高帧频图像,应用超声二维斑点追踪技术测量左室心肌各节段纵向、径向、圆周应... 目的探讨对于不同部位心肌梗死,超声二维斑点追踪技术定量判断局部室壁运动异常及心脏整体收缩功能状态的临床应用价值。方法二维超声记录左室长轴和短轴切面高帧频图像,应用超声二维斑点追踪技术测量左室心肌各节段纵向、径向、圆周应变值。结果与正常对照组对比,前壁心肌梗死组左室16/17节段的纵向应变值、11/18节段的径向应变值、12/18节段的圆周应变值减低,其中前、侧壁、室间隔及心尖部应变值减低较其余节段更为显著(P<0.05);下壁心肌梗死组左室15/17节段的纵向应变值、5/18节段的径向应变值、10/18节段的圆周应变值减低,其中下、后壁应变值减低较其余节段更为显著(P<0.05)。前壁心肌梗死组平均纵向应变、平均圆周应变及平均径向应变值均与左室射血分数(Left ventricular ejection fraction,LVEF)值显著相关(r=-0.74,r=-0.78,P<0.001;r=0.69,P<0.05),下壁心肌梗死组仅平均纵向应变值与LVEF值显著相关(r=-0.82,P<0.05)。结论超声二维斑点追踪技术是准确、定量评价心脏局部室壁运动异常及整体收缩功能新的无创方法。纵向应变值可能是全面、准确、定量评价心功能的指标,而圆周及径向应变值的作用则有待进一步研究。 展开更多
关键词 超声二维斑点追踪技术 应变 节段性室壁运动异常 心室功能
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